Deprecate Worksheet::getHashInt and Spreadsheet::getId

[oleibman]

Php8.5 may deprecate the use of __wakeup (it is planned, but not yet implemented, and it is convtroversial). We use it only twice. In the first instance, it just throws an exception to prevent a security exploit. This can be trivially replaced with __unserialize.

The other instance is merely to initialize a Worksheet instance variable. Converting this use to __unserialize is not trivial (one of the reasons for the controversy). However, I see no useful purpose for that variable. Since it has no use, there is no real need for __wakeup, so we will just remove the routine altogether, and deprecate the variable's getter (there is no setter).

A similar instance variable in Spreadsheet also serves no useful purpose, so we will deprecate its getter as well (again no setter).

This is:

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

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

Why this change is needed?

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