feat: updates person detection samples for GA

[telpirion]

This PR does the following:

• Updates person detection samples for GA (v1)
• Renames filenames to remove _beta.
• Renames region tags to remove _beta.

[snippet-bot]

Here is the summary of changes.

You added 2 region tags.

• samples/analyze/video_detect_person.py:15, tag video_detect_person
• samples/analyze/video_detect_person_gcs.py:15, tag video_detect_person_gcs

You deleted 2 region tags.

• samples/analyze/video_detect_person_beta.py:15, tag video_detect_person_beta
• samples/analyze/video_detect_person_gcs_beta.py:15, tag video_detect_person_gcs_beta

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