fix: set style property priority using proper API method

[denis-anisimov]

fixes #11981

Description

Please list all relevant dependencies in this section and provide summary of the change, motivation and context.

Fixes # (issue)

Type of change

• Bugfix
• Feature

Checklist

• I have read the contribution guide: https://vaadin.com/docs/latest/guide/contributing/overview/
• I have added a description following the guideline.
• The issue is created in the corresponding repository and I have referenced it.
• I have added tests to ensure my change is effective and works as intended.
• New and existing tests are passing locally with my change.
• I have performed self-review and corrected misspellings.

Additional for Feature type of change

• Enhancement / new feature was discussed in a corresponding GitHub issue and Acceptance Criteria were created.

[mshabarov]

@pleku the way how the important rule is identified in the input value string looks for me a bit tricky, but I don't know a better solution. The main idea behind, I believe, is to verify that the passed input contains a proper rule by parsing it through the test element and check the result of element.getStyle().getPropertyPriority(name). Unit tests and usage test are in place.
I'm not sure the line 754 is needed, but otherwise LGTM.

[CLAassistant]

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1 out of 2 committers have signed the CLA.

✅ pleku
❌ Denis Anisimov

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[vaadin-bot]

SonarQube analysis reported 2 issues

1. SimpleElementBindingStrategy.java#L1486: Refactor this code to not nest more than 3 if/for/while/switch/try statements.
2. SimpleElementBindingStrategy.java#L1492: Either log or rethrow this exception.

[vaadin-bot]

This ticket/PR has been released with platform 22.0.0.beta2 and is also targeting the upcoming stable 22.0.0 version.