[HB-6639] Adds ContainerSize to BannerView API

[kushG]

Title

HB-6639 Adds ContainerSize to bannerView API

Description

Unity developers do not have any means to get the size of the banner container since the container (BannerView )exists on native layer. With this PR they will be able to call ContainerSize to get such size.

Type of change

• Bug fix (fixes an issue)
• New feature (adds functionality)
• Refactor / Maintenance (refactoring code to be cleaner/easier to maintain)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[github-actions]

Test Results

1 tests  ±0   1 ✔️ ±0   0s ⏱️ ±0s
1 suites ±0   0 💤 ±0 
1 files   ±0   0 ❌ ±0 

Results for commit 51d892c. ± Comparison against base commit e203296.

♻️ This comment has been updated with latest results.