Dark theme: fix tab hover color

[nightnei]

How AI was used in this PR

AI implemented changes, but I manually adjusted by removing ! important and redundant generated styles.

Proposed Changes

Let's align tabs hover styles for Dark theme with Light theme.

Before:


After:

Testing Instructions

1. npm start
2. Assert that for Light theme tabs look good (default, hover, active). Also yo ucan open Studio Settings and site Settings to assert that everythign good tehre too.
3. Turn on Dark mode
4. Assert that for Dark theme tabs look good (default, hover, active) and styles aligned with Light mode (no hover effect, etc).

[wpmobilebot]

📊 Performance Test Results

Comparing 8344e59 vs trunk

app-size

Metric	trunk	8344e59	Diff	Change
App Size (Mac)	1384.39 MB	1384.39 MB	+0.00 MB	⚪ 0.0%

site-editor

Metric	trunk	8344e59	Diff	Change
load	1695 ms	1629 ms	66 ms	🟢 -3.9%

site-startup

Metric	trunk	8344e59	Diff	Change
siteCreation	9035 ms	9032 ms	3 ms	⚪ 0.0%
siteStartup	4402 ms	4399 ms	3 ms	⚪ 0.0%

---

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)

[bcotrim]

LGTM 👍
I did not find any regressions in light mode

Before	After