Importing FileTypeRouter imports all converters

[tstadel]

Describe the bug
When using/importing FileTypeRouter all converters are imported as well. This makes it a heavier operation than necessary and can increase the probability for further issues (e.g. cyclic dependencies, load-time, import deadlocks when used in multithreaded env). E.g. importing AzureOCRDocumentConverter loads additional external depencies.

Line causing this:

haystack/haystack/components/routers/file_type_router.py

Line 12 in 7829242

from haystack.components.converters.utils import get_bytestream_from_source, normalize_metadata

Error message

Expected behavior
Using/importing FileTypeRouter does not load all converters / has no dependency to converters.
E.g. the two methods in question could be moved to the haystack.utils module.

Additional context

To Reproduce

FAQ Check

• Have you had a look at our new FAQ page?

System:

• OS:
• GPU/CPU:
• Haystack version (commit or version number):
• DocumentStore:
• Reader:
• Retriever: