gh-126785: introduce frame command for pdb

[wenqiny]

#126785: This PR introduce a new command frame to switch current frame in pdb

The current PR doesn't add some test about the new frame command yet, because I don't know whether there is any automatic tool to generate some test in test_pdb.py file, if there is not, I will try to add some test manually later.

The more details is in the issue, PTAL, thanks!

• Issue: Introduces more interactive command for PDB  #126785

[ghost]

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[bedevere-app]

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If this change has little impact on Python users, wait for a maintainer to apply the skip news label instead.

[bedevere-app]

Most changes to Python require a NEWS entry. Add one using the blurb_it web app or the blurb command-line tool.

If this change has little impact on Python users, wait for a maintainer to apply the skip news label instead.

[user202729]

See more discussions on #126785 for why this is difficult.