fix: fitz import switcher (#5012)

* fix pymupdf import switcher

* install pdf

* check after the import

* revert workflow change

* pylint

* pylint

* pylint again

haystack/nodes/file_converter/__init__.py

@@ -1,3 +1,4 @@
+from haystack import is_imported
 from haystack.nodes.file_converter.base import BaseConverter
 
 from haystack.utils.import_utils import safe_import
@@ -10,16 +11,16 @@
 from haystack.nodes.file_converter.azure import AzureConverter
 from haystack.nodes.file_converter.parsr import ParsrConverter
 
+# Try to use PyMuPDF, if not available fall back to xpdf
+from haystack.nodes.file_converter.pdf import PDFToTextConverter
+
+if not is_imported("fitz"):
+    from haystack.nodes.file_converter.pdf_xpdf import PDFToTextConverter  # type: ignore  # pylint: disable=reimported
+
 
 MarkdownConverter = safe_import(
     "haystack.nodes.file_converter.markdown", "MarkdownConverter", "preprocessing"
 )  # Has optional dependencies
 ImageToTextConverter = safe_import(
     "haystack.nodes.file_converter.image", "ImageToTextConverter", "ocr"
 )  # Has optional dependencies
-
-# Try to use PyMuPDF, if not available fall back to xpdf
-try:
-    from haystack.nodes.file_converter.pdf import PDFToTextConverter
-except ImportError:
-    from haystack.nodes.file_converter.pdf_xpdf import PDFToTextConverter  # type: ignore