Reverts the logic for calculating the TextField input text cursor position when inputting Korean characters (3.13.9)

[deniz-lee]

Reverts the logic for calculating the TextField input text cursor position when inputting Korean characters (3.13.9)

• Issue occurred since 3.16.x

List which issues are fixed by this PR. You must list at least one issue.

• When entering Korean text, the input cursor must be located on the right side of the input text.
  However, when entering Korean text, the input cursor is located to the left of the entered character.

Recorded Video about the issue:

• Before (origin/main branch)
  https://github.com/flutter/engine/assets/121159478/116c849e-d149-46ce-b3e4-eadcf7239b76

• Modified (origin/text_cursor_position_incorrect_windows)
  https://github.com/flutter/engine/assets/121159478/61852bca-da6e-4864-89e1-7e787d67355b

Pre-launch Checklist

• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• I read the [Tree Hygiene] wiki page, which explains my responsibilities.
• I read and followed the [Flutter Style Guide] and the [C++, Objective-C, Java style guides].
• I listed at least one issue that this PR fixes in the description above.
• I added new tests to check the change I am making or feature I am adding, or the PR is [test-exempt]. See [testing the engine] for instructions on writing and running engine tests.
• I updated/added relevant documentation (doc comments with ///).
• I signed the [CLA].
• All existing and new tests are passing.

[flutter-dashboard]

It looks like this pull request may not have tests. Please make sure to add tests before merging. If you need an exemption to this rule, contact "@test-exemption-reviewer" in the #hackers channel in Chat (don't just cc them here, they won't see it! Use Discord!).

If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix?

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing.

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[deniz-lee]

follow up on #51164