Add raise_on_missing_reader flag to LoadImaged dictionary wrapper

- Pass through raise_on_missing_reader parameter to underlying LoadImage
- Update docstring to document the new parameter
- Ensure consistent behavior between array and dictionary versions

Author: its-serah

monai/transforms/io/dictionary.py

@@ -87,6 +87,7 @@ def __init__(
         prune_meta_sep: str = ".",
         allow_missing_keys: bool = False,
         expanduser: bool = True,
+        raise_on_missing_reader: bool = False,
         *args,
         **kwargs,
     ) -> None:
@@ -123,6 +124,8 @@ def __init__(
                 e.g. ``prune_meta_pattern=".*_code$", prune_meta_sep=" "`` removes meta keys that ends with ``"_code"``.
             allow_missing_keys: don't raise exception if key is missing.
             expanduser: if True cast filename to Path and call .expanduser on it, otherwise keep filename as is.
+            raise_on_missing_reader: if True, raise OptionalImportError when a specified reader is not available,
+                otherwise attempt to use fallback readers. Default is False to maintain backward compatibility.
             args: additional parameters for reader if providing a reader name.
             kwargs: additional parameters for reader if providing a reader name.
         """
@@ -136,6 +139,7 @@ def __init__(
             prune_meta_pattern,
             prune_meta_sep,
             expanduser,
+            raise_on_missing_reader,
             *args,
             **kwargs,
         )