Fix a crash in Krita due to accessing to an unsupported action in TextTool

The action "insert_table" (as well as other table-related actions) is added
by the Text Tool only in case the app supports 'useAdvancedText' feature.

That is why accessing the "insert_table" outside 'useAdvancedText' check
will cause a crash.

Please revert/change this commit if I understood something wrong :)


CC