Several fixups for unicode normalization

[LeonarddeR]

Link to issue number:

Fixup of #16521
Fixes #11570
Partial fix for #4631

Summary of the issue:

1. It turns out that rawTextTypeforms on a region may be None, this was an oversight on my end.
2. cursorPos may also be None.
3. @burmancomp reported a zero division error in case a string ended with a non breaking space and a space.

Description of user facing changes

No longer errors in the log when getting flash messages in Thunderbird and/or reading messages in WhatsApp UWP.

Description of development approach

1. Explicitly check for None typeforms and cursorPos, thereby improving readability as well.
2. Improve the calculateOffsets method in textUtils to ensure it can handle the case as reported by @burmancomp

Testing strategy:

From a python console
braille.TextRegion("ij").update()
No longer results in an error.
Same for braille.TextRegion("\xa0 ").update()

Known issues with pull request:

None known

Code Review Checklist:

• Documentation:
  • Change log entry
  • User Documentation
  • Developer / Technical Documentation
  • Context sensitive help for GUI changes
• Testing:
  • Unit tests
  • System (end to end) tests
  • Manual testing
• UX of all users considered:
  • Speech
  • Braille
  • Low Vision
  • Different web browsers
  • Localization in other languages / culture than English
• API is compatible with existing add-ons.
• Security precautions taken.

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• Build execution time has reached the maximum allowed time for your plan (60 minutes).

See test results for failed build of commit 740467ce53

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See test results for failed build of commit b9ed18e76b

[LeonarddeR]

@burmancomp reported a zero division error when doing:
textUtils.UnicodeNormalizationOffsetConverter("removed original text\xa0 ")

[AppVeyorBot]

• Build execution time has reached the maximum allowed time for your plan (60 minutes).

See test results for failed build of commit e687938887

[LeonarddeR]

I think for now, we could probably best leave this as is. Note that there are still some open questions, but these can be handled in a follow up:

1. Whether unicode normalization should be disabled by default (I think it still should),. That said, we should be able to change the default without breaking explicit configurations, hence the feature flag with combo box approach.
2. Whether character navigation should also normalize. It currently doesn't, and I think there's a real good reason for it. An option to consider is to report the normalized character preceded by the word normalized, but in other languages (e.g. in Dutch) this will probably be very weird and confusing. Other options hook into the character descriptions mechanism.

[seanbudd]

Thanks @LeonarddeR

[Qchristensen]

Looks good

[seanbudd]

@LeonarddeR - are these 2 things tracked in a separate issue or discussion? I think they'd be good to discuss for 2024.4