Survey-wide recursive numbering works incorrectly when survey pages have titles and `questionStartIndex` is a multi-level number

[andrewtelnov]

The following JSON works incorrectly. The question numbers are wrong:

{
    pages: [
      {
        title: "Page 1",
        elements: [
          { type: "text", name: "q1" },
          { type: "text", name: "q2" }
        ]
      },
      {
        title: "Page 2",
        elements: [
          { type: "text", name: "q3" },
          { type: "text", name: "q4" },
          { type: "panel", name: "p1", title: "panel", showNumber: true, elements: [
            { type: "text", name: "q5" }
          ] }
        ]
      }
    ],
    showQuestionNumbers: "recursive",
    questionStartIndex: "1.1"
  }