fix: suggest true/false completions for BOOLEAN params in interactive mode

[jja6312]

Summary

Fixes #1056

In interactive mode (oci -i), BOOLEAN parameters had no completion
suggestions when pressing Tab. This caused an error in the bottom toolbar
because the completer fell through to the resource-fetching path, which
is incorrect for BOOLEAN types.

Changes

• Added check_param_is_bool() helper in oci_shell_completer.py,
  following the same pattern as the existing check_param_is_flag()
• Added a click.BOOL branch in get_completions() that returns
  true and false as completions

How to Validate

1. Start interactive mode: oci -i
2. Type and press Tab after a BOOLEAN parameter:
   oci iam compartment list --compartment-id-in-subtree <TAB>
3. true and false now appear as suggestions

Before

After

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