Update nimi-bot RHEL runner from 8.3 to 9.6

[rahur-NI]

• This contribution adheres to CONTRIBUTING.md.
• I've updated CHANGELOG.md if applicable.
• I've added tests applicable for this pull request

What does this Pull Request accomplish?

• Upgraded nimi-bot RHEL Python64 runner version from 8.3 to 9.6
• Disabled failing NI-Scope system test(test_filter_coefficients, test_configure_trigger_video). These need persistent simulated 5142/5124 devices which are having issues with RHEL 9.6 version. Decision is to accept this gap to unblock other PR contributions until the issue is fully resolved.

What testing has been done?

• A successful tox execution.
• All existing system tests are passing.
• Intermittent issue with exit code -6 (SIGABRT) was observed in some runs. Tried to gather information for this failure but unsuccessful due to its flaky nature.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.32%. Comparing base (ab52ec6) to head (2bed519).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2180      +/-   ##
==========================================
- Coverage   89.85%   89.32%   -0.53%     
==========================================
  Files          73       73              
  Lines       19006    19048      +42     
==========================================
- Hits        17077    17015      -62     
- Misses       1929     2033     +104     

Flag	Coverage Δ
codegenunittests	84.90% <ø> (ø)
nidcpowersystemtests	94.38% <ø> (-0.23%)	⬇️
nidcpowerunittests	89.53% <ø> (ø)
nidigitalsystemtests	92.02% <ø> (-0.24%)	⬇️
nidigitalunittests	68.44% <ø> (ø)
nidmmsystemtests	92.29% <ø> (-0.44%)	⬇️
nifakeunittests	86.01% <ø> (ø)
nifgensystemtests	94.32% <ø> (-0.30%)	⬇️
nimodinstsystemtests	73.85% <ø> (ø)
nimodinstunittests	94.20% <ø> (ø)
nirfsgsystemtests	81.12% <ø> (ø)
niscopesystemtests	89.96% <ø> (-2.99%)	⬇️
niscopeunittests	43.20% <ø> (ø)
nisesystemtests	91.50% <ø> (ø)
niswitchsystemtests	81.56% <ø> (-0.48%)	⬇️
nitclksystemtests	94.87% <ø> (ø)
nitclkunittests	98.26% <ø> (ø)

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see 10 files with indirect coverage changes

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[vnktshr21]

Going ahead and approving the changes since no actual tests of the API are failing because of new changes. And with this change merged, it unblocks future submissions for now, even with the intermittent failures.