Implement Sort by Project dropdown in Checks Side Panel

[katherinejensen00]

User Story
As a user, I want to be able to filter the check results by project I see so that I only see the ones from the project I am interested in working on at the time and don't get distracted by or lost in irrelevant results.

Description
Implement filtering by project as described in the "Filtering for checks to run" section of Figma design

Depends on
Partially depends on Checks Set Up component
Related to Filters/Configuration for Checks Side Panel component

Implementation idea

• Create (or enable if already created but greyed out) UI for the project dropdown and dynamically fill it with available projects
• Implement filtering the checks results by project
• Note, opening a new editor when the project is selected is part of a different task, Open New Editor when Project Changed in Checks Side Panel #1380

Testing ideas

• Select a project from the dropdown and verify all of the checks in the side panel are from that project
• This change is related to a different case that will open a new editor when the project changes, Open New Editor when Project Changed in Checks Side Panel #1380, after that this functionality should be fairly stable.