Minor Python bugfixes and type issues

[nullableVoidPtr]

• Fixed parameters for get_incoming_flag_value
• Disambiguated return type for TypedDataAccessor.__getitem__ (previously TypedDataAcccessor | List[TypedDataAccessor] no matter the type for key)
• Fixed parameter type conflicts in types, primarily in TypeBuilders
• Disambiguated return type for data/text/line searchers in a BinaryView
• Specify callback type and convert match callback param for BinaryView.find_all_text
• Allow user-specified joins for a Python QualifiedName

[nullableVoidPtr]

For additional context, these are issues I came across polishing my plugin

[nullableVoidPtr]

That being said, I feel like a TypeProtocol would be rather useful for easier typing when Type or TypeBuilder can be used - though I have not tested this.