For #2834: Delete all Private Tabs redesign

[jyeontaek]

Pull Request checklist

• Quality: This PR builds and passes detekt/ktlint checks (A pre-push hook is recommended)
• Tests: This PR includes thorough tests or an explanation of why it does not
• Changelog: This PR includes a changelog entry or does not need one
• Accessibility: The code in this PR follows accessibility best practices or does not include any user facing features

[jyeontaek]

@sblatz Did we want to add tests for this feature as well?

[codecov-io]

Codecov Report

Merging #4787 into master will decrease coverage by 0.03%.
The diff coverage is 0%.

@@             Coverage Diff             @@
##             master   #4787      +/-   ##
===========================================
- Coverage      7.05%   7.02%   -0.04%     
  Complexity      145     145              
===========================================
  Files           213     213              
  Lines          8978    8988      +10     
  Branches       1352    1355       +3     
===========================================
- Hits            633     631       -2     
- Misses         8305    8317      +12     
  Partials         40      40

Impacted Files	Coverage Δ	Complexity Δ
.../sessioncontrol/viewholders/TabHeaderViewHolder.kt	0% <0%> (ø)	0 <0> (ø)	⬇️
...c/main/java/org/mozilla/fenix/home/HomeFragment.kt	0% <0%> (ø)	0 <0> (ø)	⬇️
...rc/main/java/org/mozilla/fenix/BrowserDirection.kt	100% <0%> (ø)	2% <0%> (ø)	⬇️

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[sblatz]

@jyeontaek just some linting errors to fix too: