Introduce branding support for push authentication screen

[pavinduLakshan]

Purpose

$subject

Related Issues

• Branding preview for the push authentication page is not working as expected product-is#22634

Related PRs

• N/A

Checklist

• e2e cypress tests locally verified. (for internal contributers)
• Manual test round performed and verified.
• UX/UI review done on the final implementation.
• Documentation provided. (Add links if there are any)
• Relevant backend changes deployed and verified
• Unit tests provided. (Add links if there are any)
• Integration tests provided. (Add links if there are any)

Security checks

• Followed secure coding standards in http://wso2.com/technical-reports/wso2-secure-engineering-guidelines
• Ran FindSecurityBugs plugin and verified report
• Confirmed that this PR doesn't commit any keys, passwords, tokens, usernames, or other secrets

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 41.98%. Comparing base (e1fd42a) to head (a0c8ecf).
Report is 31 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #7509   +/-   ##
=======================================
  Coverage   41.98%   41.98%           
=======================================
  Files          42       42           
  Lines         936      936           
  Branches      233      227    -6     
=======================================
  Hits          393      393           
  Misses        499      499           
  Partials       44       44           

Flag	Coverage Δ
@wso2is/core	41.98% <ø> (ø)

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