compute: add name_prefix to google_compute_managed_ssl_certificate (#8889)

[jbbqqf]

Summary

Adds name_prefix support to google_compute_managed_ssl_certificate,
mirroring the existing name_prefix on google_compute_ssl_certificate.
Users practising cert rotation typically need to recreate certs with
stable prefixes (so the new cert exists side-by-side with the old before
swap), and they want Terraform to generate the unique trailing suffix
automatically. Without name_prefix, they must use random_id
workarounds or imperative wrappers.

Fixes hashicorp/terraform-provider-google#8889 — see hashicorp/terraform-provider-google#8889

Why

The user-managed google_compute_ssl_certificate already supports
name_prefix via a shared extra_schema_entry and custom_expand
(mmv1/templates/terraform/extra_schema_entry/ssl_certificate.tmpl and
mmv1/templates/terraform/custom_expand/name_or_name_prefix.go.tmpl).
The Google-managed variant has the same lifecycle constraint
(certificates are immutable, must be rotated by replacement) and the
same underlying API resource (compute#sslCertificate) — so the same
prefix-generation logic applies as-is.

GCP API reference:

• https://cloud.google.com/compute/docs/reference/rest/v1/sslCertificates
• https://cloud.google.com/load-balancing/docs/ssl-certificates

What changed

This change is to a mmv1-generated resource. Files touched in
magic-modules:

 mmv1/products/compute/ManagedSslCertificate.yaml | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

The YAML edits:

1. Added a docs.optional_properties entry documenting name_prefix (same
   wording as SslCertificate.yaml).
2. Added extra_schema_entry: 'templates/terraform/extra_schema_entry/ssl_certificate.tmpl'
   to the custom_code block (which already had a constants entry).
3. Added default_from_api: true and custom_expand: '.../name_or_name_prefix.go.tmpl'
   to the name property — same shape as the name field on SslCertificate.yaml.
4. Added ignore_read_extra: ['name_prefix'] to both examples (matches the
   pattern from SslCertificate.yaml's examples — name_prefix is a
   client-side-only field with no read counterpart).

Edge cases tested

#	Scenario	HCL excerpt	Expected	Verified by
1	name set, name_prefix unset	name = "my-cert"	Existing behavior unchanged	Regen schema diff: name is still Optional+Computed, ConflictsWith: []string{"name_prefix"}
2	name_prefix set, name unset	name_prefix = "rotation-"	name computed by id.PrefixedUniqueId(prefix)	custom_expand template emits the same logic as SslCertificate (prefix > 37 → ReducedPrefixedUniqueId, else id.PrefixedUniqueId)
3	Both set	name = "x"; name_prefix = "y-"	Plan-time error from ConflictsWith validator	The shared ssl_certificate.tmpl schema entry has ConflictsWith: []string{"name"}
4	name_prefix exceeds 54 chars	name_prefix = strings.Repeat("a", 55)	Plan-time validation error	Shared ValidateFunc rejects len > 54

Test protocol

Test	Result	Notes
YAML lint (go run mmv1/. --output ... --version ga --no-docs)	OK	Regeneration completed cleanly
go build ./google/services/compute/... (TPG)	OK	full compute service compiles
go vet ./google/services/compute/... (TPG)	OK	no new findings (3 pre-existing unreachable-code warnings in firewall_policy files are unchanged by this PR)
Generated schema includes name_prefix field	OK	grep'd resource_compute_managed_ssl_certificate.go after regen — confirms name_prefix schema entry, ConflictsWith: []string{"name"}, and the expand-name handler
Generated name field is computed-from-prefix	OK	expandComputeManagedSslCertificateName follows the shared template: returns name when set, else id.PrefixedUniqueId(name_prefix), else id.UniqueId()

This is a purely additive client-side schema extension (the API
already accepts whatever name the client supplies — there is no API-side
change). Live smoke is therefore not strictly necessary for confidence,
and Google-managed cert provisioning is slow/expensive (30-min create
timeout) which makes it costly. The static evidence is identical to
what's been used for the user-managed SslCertificate name_prefix for
years.

Resources

• Issue: Add name_prefix support to google_compute_managed_ssl_certificate hashicorp/terraform-provider-google#8889
• Sibling resource (already supports name_prefix):
  https://github.com/jbbqqf/magic-modules/blob/main/mmv1/products/compute/SslCertificate.yaml
• mmv1 file:
  https://github.com/jbbqqf/magic-modules/blob/feat/8889-managed-ssl-cert-name-prefix/mmv1/products/compute/ManagedSslCertificate.yaml

Disclosure

This PR was implemented with assistance from Claude Code. The diff was
modeled on the existing SslCertificate.yaml name_prefix wiring — a
well-tested pattern that's been in the provider for years — and the
regenerated provider compiled and vetted cleanly. The author (a human)
reviewed the diff and the regenerated schema before opening this PR.