chore: make sidecar container change backward compatible

[whynowy]

#2230

Tested in k8s < 1.29, it worked.

[codecov]

Codecov Report

Attention: Patch coverage is 45.65217% with 25 lines in your changes missing coverage. Please review.

Project coverage is 63.90%. Comparing base (c5afc90) to head (d6addec).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/reconciler/cmd/start.go	0.00%	8 Missing ⚠️
pkg/apis/numaflow/v1alpha1/side_inputs.go	71.42%	3 Missing and 1 partial ⚠️
pkg/apis/numaflow/v1alpha1/container_builder.go	25.00%	2 Missing and 1 partial ⚠️
pkg/apis/numaflow/v1alpha1/mono_vertex_types.go	50.00%	2 Missing and 1 partial ⚠️
pkg/apis/numaflow/v1alpha1/vertex_types.go	40.00%	2 Missing and 1 partial ⚠️
pkg/apis/numaflow/v1alpha1/deprecated.go	71.42%	2 Missing ⚠️
pkg/reconciler/isbsvc/controller.go	0.00%	1 Missing ⚠️
pkg/reconciler/pipeline/controller.go	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2236      +/-   ##
==========================================
- Coverage   63.91%   63.90%   -0.01%     
==========================================
  Files         338      339       +1     
  Lines       41085    41118      +33     
==========================================
+ Hits        26259    26276      +17     
- Misses      13756    13769      +13     
- Partials     1070     1073       +3     

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