Improve import error detection so the plugin does not throw errors in headless mode

[asesidaa]

Recently when I tried to run IDA in headleass mode via scripting in Claude Code, I noticed that the following error is thrown by this plugin:

Traceback (most recent call last):
  File "H:\ida/plugins\pyclassinformer\qtutils.py", line 10, in can_use_qt
    import sip
ModuleNotFoundError: No module named 'sip'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "H:\ida/plugins\pyclassinformer\qtutils.py", line 131, in ready_to_run
    self.enable_toolbar()
    ~~~~~~~~~~~~~~~~~~~^^
  File "H:\ida/plugins\pyclassinformer\qtutils.py", line 135, in enable_toolbar
    set_toobar_visible(widget, self.toolbar_name)
    ~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "H:\ida/plugins\pyclassinformer\qtutils.py", line 106, in set_toobar_visible
    if not can_use_qt():
           ~~~~~~~~~~^^
  File "H:\ida/plugins\pyclassinformer\qtutils.py", line 17, in can_use_qt
    from PySide6 import QtCore
  File "H:\ida\python\PySide6\__init__.py", line 26, in <module>
    _verify_prerequisites()
    ~~~~~~~~~~~~~~~~~~~~~^^
  File "H:\ida\python\PySide6\__init__.py", line 19, in _verify_prerequisites
    raise ImportError("PySide6 can only be used from the GUI version of IDA")
ImportError: PySide6 can only be used from the GUI version of IDA

Although there is existing exception handling, it does not catch the error when running in headless mode.
Here's the analysis Claude gives:

What was wrong: The pyclassinformer IDA plugin's qtutils.py had a broken exception handling pattern when PyQt5 import failed with ModuleNotFoundError (subclass of ImportError), it fell into except ImportError and tried PySide6, which also failed in headless mode. That second failure wasn't caught.

Fix: Wrapped all PySide6 fallback imports in their own try/except (ImportError, ModuleNotFoundError) blocks across 8 functions