[Refactoring] Refined styles for quality page

[klakhov]

Motivation and context

This PR refactors the quality page styles, specifically the tables. Currently, the page layout consists of some static elements and a table with dynamic height. If the table is too large, a scrollbar appears.

Previously, the table’s height was limited using max-height: calc(100vh - $grid-unit-size * x);. However, this approach isn’t ideal because, on smaller screens (especially those with a width under 1800px) or when scaling the page, the height needs further adjustments. While media queries could help, they introduce complexity.

This PR updates the layout to use a flexbox-based approach instead. The main page now has display: flex, and the table inside it uses flex-grow: 1 to fill the remaining space dynamically. To make this work, I also flattened the component structure by removing unnecessary containers.

Additionally, I added a media query breakpoint that makes the page scrollable when the width is below 1300px.

How has this been tested?

Checklist

• I submit my changes into the develop branch
• [ ] I have created a changelog fragment
• [ ] I have updated the documentation accordingly
• [ ] I have added tests to cover my changes
• [ ] I have linked related issues (see GitHub docs)

License

• I submit my code changes under the same MIT License that covers the project.
  Feel free to contact the maintainers if that's a concern.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

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Additional details and impacted files

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Components	Coverage Δ
cvat-ui	77.42% <ø> (?)
cvat-server	70.68% <ø> (?)