use project scales in label rendering and new 2D canvas dock if they are set (fix #51326)

[alexbruy]

Description

When user overrides global scales list in the project properties, QGIS uses this overriden list in the scale selector in the status bar, in the atlas settings, in the layer and diagrams rendering settings. However, in it does not applied to the label rendering settings and in the new 2D map views.

Fixes #51326.

[github-actions]

🪟 Windows builds ready!

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(Built from commit 3c3f7da)

[github-actions]

The QGIS project highly values your contribution and would love to see this work merged! Unfortunately this PR has not had any activity in the last 14 days and is being automatically marked as "stale". If you think this pull request should be merged, please check

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[alexbruy]

Not stale

[alexbruy]

@nyalldawson may I ask your opinion on this?

[github-actions]

The QGIS project highly values your contribution and would love to see this work merged! Unfortunately this PR has not had any activity in the last 14 days and is being automatically marked as "stale". If you think this pull request should be merged, please check

• that all unit tests are passing

• that all comments by reviewers have been addressed

• that there is enough information for reviewers, in particular

  • link to any issues which this pull request fixes

  • add a description of workflows which this pull request fixes

  • add screenshots if applicable

• that you have written unit tests where possible
  In case you should have any uncertainty, please leave a comment and we will be happy to help you proceed with this pull request.
  If there is no further activity on this pull request, it will be closed in a week.

[github-actions]

While we hate to see this happen, this PR has been automatically closed because it has not had any activity in the last 21 days. If this pull request should be reconsidered, please follow the guidelines in the previous comment and reopen this pull request. Or, if you have any further questions, just ask! We love to help, and if there's anything the QGIS project can do to help push this PR forward please let us know how we can assist.

[nyalldawson]

Superseded by #57160