Fix for flaky behavior of test_incentive, test_commit_weights and test_set_weights

[basfroman]

Includes:

• fixed a few small bugs.
• added skipping the test if it flaky (we run 5 versions of tests on different supported python versions)

AC:

• Add period to set_weights for fast block subnet-template#4 merged
• specific_commit="92d5bdf1069286d97470362c5c22611aa0fa048c" removed from PR

Observation:

• workflows/jobs launched using Python 3.13 take 1.5-2 times longer to complete
• subnet-template required some changes (weights were set frequently and without a period (for fast blocks))
• the chain takes longer to release data if running at low power
• ubuntu-latest GH runner is really faster than custom SubtenroCI one
• during local testing, reduce docker resources to a minimum. This will show more resource-sensitive operations.
• error code 1012 means the transaction with the same data can get in pool black-list. see this post

Created issues/tickets:

• Add period or era object as argument to all extrinsic #2810