feat: move atm to v1beta1

[zhiying-lin]

What type of PR is this?
/kind feature

What this PR does / why we need it:
upgrade atm feature from v1alpha1 to v1beta1

Which issue(s) this PR fixes:

Fixes #

Requirements:

• run make reviewable for basic local test
• Read and followed fleet-networking's Code of conduct.
• uses conventional commit messages
• includes documentation
• adds unit tests

How has this code been tested

e2e tests are green
https://github.com/Azure/fleet-networking/actions/runs/12649798257

Special notes for your reviewer

docs will be fixed in a separate PR.

[codecov]

Codecov Report

Attention: Patch coverage is 92.75362% with 5 lines in your changes missing coverage. Please review.

Project coverage is 80.10%. Comparing base (f7a05d8) to head (8071c15).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...ontrollers/hub/trafficmanagerbackend/controller.go	92.00%	2 Missing and 2 partials ⚠️
...ontrollers/hub/trafficmanagerprofile/controller.go	93.75%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #244      +/-   ##
==========================================
+ Coverage   79.90%   80.10%   +0.20%     
==========================================
  Files          27       27              
  Lines        3846     3851       +5     
==========================================
+ Hits         3073     3085      +12     
+ Misses        618      612       -6     
+ Partials      155      154       -1     

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