Fix header look and feel changes

[LDrago27]

Description

The changes in the PR aims at improving the look and feel of the Application header.

• Change the titles of new Dashboard - New dashboard, Visualization - New visualization, Discover - New search
• Fix padding & spacing issues in visualization landing page
• Fix margin for the Add an existing object to the dashboard wizard

Issues Resolved

Screenshot

Testing the changes

Changelog

• Fix header look and feel changes for Discover, Dashboards and Visualization Pages

Check List

• All tests pass
  • yarn test:jest
  • yarn test:jest_integration
• New functionality includes testing.
• New functionality has been documented.
• Update CHANGELOG.md
• Commits are signed per the DCO using --signoff

[github-actions]

❌ Empty Changelog Section

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[github-actions]

❌ Invalid Prefix

Invalid description prefix. Found "Fix header look and feel changes for Discover, Dashboards and Visualization Pages". Expected "breaking", "deprecate", "feat", "fix", "infra", "doc", "chore", "refactor", "security", "skip", or "test".

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 60.60%. Comparing base (4776fcd) to head (47f8c1d).
Report is 7 commits behind head on main.

Files with missing lines	Patch %	Lines
...components/dashboard_top_nav/dashboard_top_nav.tsx	0.00%	0 Missing and 1 partial ⚠️
...s_react/public/table_list_view/table_list_view.tsx	0.00%	1 Missing ⚠️
..._builder/public/application/components/top_nav.tsx	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8064      +/-   ##
==========================================
+ Coverage   60.59%   60.60%   +0.01%     
==========================================
  Files        3738     3738              
  Lines       88645    88647       +2     
  Branches    13765    13767       +2     
==========================================
+ Hits        53714    53728      +14     
+ Misses      31653    31641      -12     
  Partials     3278     3278              

Flag	Coverage Δ
Linux_1	28.76% <0.00%> (-0.01%)	⬇️
Linux_2	56.27% <ø> (ø)
Linux_3	37.51% <0.00%> (+<0.01%)	⬆️
Linux_4	29.61% <0.00%> (-0.01%)	⬇️
Windows_1	28.79% <0.00%> (+0.01%)	⬆️
Windows_2	56.22% <ø> (ø)
Windows_3	37.51% <0.00%> (-0.01%)	⬇️
Windows_4	29.61% <0.00%> (-0.01%)	⬇️

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[AMoo-Miki]

Note: The space below the search box will be addressed when opensearch-project/oui#1391 lands in OSD.