Fix TEXT and TIMEVALUE Functions 2.1 Branch

[oleibman]

Fix #4249. Technically speaking, only the 1.29 branch needs fixing, and only for TEXT. It was fixed for the other branches by PR #3898. However, in adding test cases for the fix, it became apparent that PhpSpreadsheet's parsing in TIMEVALUE (which is called from TEXT in the original issue) did not really match Excel's. There are probably still edge cases where it doesn't, but, in the absence of a spec for how it operates, this will do for now.

We do not usually backport fixes from the master branch. Because this is more of a forward port from the earlier branch, there is an equivalent PR for each active branch.

This is:

• a bugfix
• a new feature
• refactoring
• additional unit tests

Checklist:

• Changes are covered by unit tests
  • Changes are covered by existing unit tests
  • New unit tests have been added
• Code style is respected
• Commit message explains why the change is made (see https://github.com/erlang/otp/wiki/Writing-good-commit-messages)
• CHANGELOG.md contains a short summary of the change and a link to the pull request if applicable
• Documentation is updated as necessary