change: Allow telemetry only in supported regions

[rsareddy0329]

Issue #, if available:
There is a security vulnerability with the current telemetry setup where the AWS control through unclaimed S3-buckets

Description of changes:

• Added list of regions supported for telemetry logging : [src/sagemaker/telemetry/constants.py]
• Added validation for the region if it exists in the current supported ones : [src/sagemaker/telemetry/telemetry_logging.py]
• Added unit tests to verify the validation code: [tests/unit/sagemaker/telemetry/test_telemetry_logging.py]

Testing done:
yes, added unit tests for the code change and tested it.

Merge Checklist

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General

• I have read the CONTRIBUTING doc
• I certify that the changes I am introducing will be backward compatible, and I have discussed concerns about this, if any, with the Python SDK team
• I used the commit message format described in CONTRIBUTING
• I have passed the region in to all S3 and STS clients that I've initialized as part of this change.
• I have updated any necessary documentation, including READMEs and API docs (if appropriate)

Tests

• I have added tests that prove my fix is effective or that my feature works (if appropriate)
• I have added unit and/or integration tests as appropriate to ensure backward compatibility of the changes
• I have checked that my tests are not configured for a specific region or account (if appropriate)
• I have used unique_name_from_base to create resource names in integ tests (if appropriate)
• If adding any dependency in requirements.txt files, I have spell checked and ensured they exist in PyPi

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[nargokul]

Lets change to logger.warning

[nargokul]

Isnt this redundant? This condition is already covered in _get_region_or_default

[rsareddy0329]

so, _get_region_or_default covers the condition where session is available but the region value is not allocated.
The else part takes care of the condition when session details are not available.

[nargokul]

It seems like we are assigning the same thing in 2 different places which is something we can simplify.

By removing the if session condition here in line195 and handling everything within _get_region_or_default

If session is None , it will automatically raise an Exception and will get assigned the default value in L#278.