[Android SDK] Edge to edge main activity doesnt handle well 3 button navigation

[kidinov]

Closes: #13455

Description

I noticed that as not all fragments in the main activity use bottom navigation, then in the cases when 3 buttons navigation is used, part of the fragment is hidden behind the navigation. The ideal solution would be to adopt all the fragments, but it's out of the scope for the target SDK project

Also, thanks to @atorresveiga, I realized that the main activity doesn't handle the case when a phone in landscape mode with three-button navigation, then the buttons are placed on a side (I beleave that in older versions they were on the bottom)
This PR also addresses that

Testing information

• Try Android 35 and below
• Try landscape and portrait mode with 3 button navigation enabled and without
• Try different fragments on the main screen

The tests that have been performed

above

Images/gif

• I have considered if this change warrants release notes and have added them to RELEASE-NOTES.txt if necessary. Use the "[Internal]" label for non-user-facing changes.

Reviewer (or Author, in the case of optional code reviews):

Please make sure these conditions are met before approving the PR, or request changes if the PR needs improvement:

• The PR is small and has a clear, single focus, or a valid explanation is provided in the description. If needed, please request to split it into smaller PRs.
• Ensure Adequate Unit Test Coverage: The changes are reasonably covered by unit tests or an explanation is provided in the PR description.
• Manual Testing: The author listed all the tests they ran, including smoke tests when needed (e.g., for refactorings). The reviewer confirmed that the PR works as expected on big (tablet) and small (phone) in case of UI changes, and no regressions are added.

[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce-Wear Android by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce-Wear Android
	Platform	⌚️ Wear OS
	Flavor	Jalapeno
	Build Type	Debug
	Commit	43d92e5
	Direct Download	woocommerce-wear-prototype-build-pr13460-43d92e5.apk

[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce Android by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce Android
	Platform	📱 Mobile
	Flavor	Jalapeno
	Build Type	Debug
	Commit	43d92e5
	Direct Download	woocommerce-prototype-build-pr13460-43d92e5.apk

[wpmobilebot]

Version 21.7 has now entered code-freeze, so the milestone of this PR has been updated to 21.8.

[samiuelson]

LGTM!