BUG: fixed issue where Index was being accessed with DatetimeIndex attribute
- [x] Closes #49925 
- [x] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature
- [x] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [x] Added [type annotations](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#type-hints) to new arguments/methods/functions.
- [x] Added an entry in the latest `doc/source/whatsnew/vX.X.X.rst` file if fixing a bug or adding a new feature.

Changes: updated the dates method in pandas/tseries/holiday.py to include a check to prevent the DatetimeIndex attribute
from being accessed by an Index object.  The bug occurs if the holidays land outside the provided date range which results in an empty DatetimeIndex object being converted to an Index object. The updated dates method now checks if the object contains elements before allowing access to a DatetimeIndex attribute because such an object will be of type Index. Furthermore, the Index object is converted back into a DatetimeIndex object. A test was added to pandas/tests/tseries/holiday/test_holiday.py to ensure that the intended behavior is occurring. 

This pull request is stale because it has been open for thirty days with no activity. Please [update](https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#updating-your-pull-request) and respond to this comment if you're still interested in working on this. Thanks for the pull request, but it appears to have gone stale. If interested in continuing, please merge in the main branch, address any review comments and/or failing tests, and we can reopen.