fix: empty string displayed as SelectDropdown title

[imorland]

Reverts the change to using extractText introduced in #3608

Whilst using extractText, the button title is rendered as an empty string. This PR reverts that change so that expected behaviour is restored.

Changes proposed in this pull request:

Reviewers should focus on:

Screenshot

Necessity

• Has the problem that is being solved here been clearly explained?
• If applicable, have various options for solving this problem been considered?
• For core PRs, does this need to be in core, or could it be in an extension?
• Are we willing to maintain this for years / potentially forever?

Confirmed

• Frontend changes: tested on a local Flarum installation.
• Backend changes: tests are green (run composer test).
• Core developer confirmed locally this works as intended.
• Tests have been added, or are not appropriate here.

Required changes:

• Related documentation PR: (Remove if irrelevant)
• Related core extension PRs: (Remove if irrelevant)

[SychO9]

@imorland was his tested locally and with the affected extensions? I haven't tested it myself

[davwheat]

Could we also document what this issue was affecting (e.g., an example of an extension where this was a problem)?

[imorland]

Example of fof/discussion-language:

Flarum 1.7.1:

With this patch:

[imorland]

@imorland was his tested locally and with the affected extensions? I haven't tested it myself

Yes, tested locally - all good