Add width constraints for FlexibleSpaceBar.title in its expanded state, so that overflow of long titles can be handled

[perclasson]

Add width constraints for FlexibleSpaceBar.title in its expanded state, so that overflow of long titles can be handled.

See this dartpad for reproducible example of the issue.

Description

Add width constraints for FlexibleSpaceBar.title in its expanded state, so that overflow of long titles can be handled.

Before:

After:

Example with larger text scale factor:

Related Issues

Closes #14227

Tests

I added the following tests:

• FlexibleSpaceBar sets width constraints for the title

Checklist

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Breaking Change

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[fluttergithubbot]

It looks like this pull request may not have tests. Please make sure to add tests before merging. If you need an exemption to this rule, contact Hixie.

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing.

[pennzht]

You can add a code snippet to the PR description to clarify what issue is being solved.

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[googlebot]

CLAs look good, thanks!

ℹ️ Googlers: Go here for more info.

[rami-a]

LGTM

[HansMuller]

LGTM