fix(ansible): respect inline checkov:skip on block tasks

[m-khan-97]

Summary

• Fixes inline checkov:skip suppression silently ignored for Ansible block checks #7501: inline checkov:skip=CKV2_ANSIBLE_3:... (and any other graph check) comments placed on an Ansible block: task were silently ignored, so the check always reported FAILED instead of SKIPPED.
• Root cause: in checkov/ansible/utils.py, _process_blocks built the suppression-context key for a block as f"{prefix}.{name}" where prefix already ends in "." (e.g. "block."), producing "block..name". The graph builder (checkov/ansible/graph_builder/local_graph.py) creates the corresponding vertex ID as f"{prefix}{name}" → "block.name". The mismatched keys meant the skip lookup in the suppression logic never found the resource's skip comment.
• Fix removes the extra ., so the context key now matches the graph vertex ID exactly, the same way generate_task_name already does for non-block tasks.

Test plan

• Added tests/ansible/examples/block_skip.yml reproducing the reported scenario (a block: task with an inline checkov:skip=CKV2_ANSIBLE_3 comment).
• Added test_runner_with_block_skip in tests/ansible/test_runner.py (parametrized over both graph connectors) asserting the check is now reported as SKIPPED with the correct resource id.
• Ran the full tests/ansible/ suite locally — all existing tests still pass (no regressions for flat tasks, blocks, or nested blocks).
• Manually reproduced the original bug and confirmed the fix resolves it:

  checkov -f test_skip.yml --framework ansible --check CKV2_ANSIBLE_3 --compact
  # before: FAILED for resource: block.Block with inline skip comment
  # after:  SKIPPED for resource: block.Block with inline skip comment