Fix which error used

Some errors are duplicated and may never be called.
These errors exist in both fp and fp-ocr or fp-transcription
NotTranscriptionApplicableError
NotOCRApplicableError,
TesseractNotFound

A good starting place is the test_x_decorator files in file-processing. Their home library test files too.

Fix could be removing respective errors from home libraries, however this will impact test cases.
Also cant make fp a dependency of fp-ocr and fp-transcription because that's circular.
Maybe just check for whatever native python error in fp-ocr and fp-transcription tests.