BUG: read_excel not forward filling index columns when no names are given
- [x] closes #47487 (Replace xxxx with the Github issue number)
- [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.


The prevoious has_index_name routine was too simple. This version is aligned with the TextReader version that is used a few lines below
```
pandas/io/excel/_base.py:793: error: List item 0 has incompatible type "Union[int, Sequence[int]]"; expected "int"  [list-item]
pandas/io/excel/_base.py:797: error: Argument 1 to "len" has incompatible type "Union[int, Sequence[int], None]"; expected "Sized"  [arg-type]
pandas/io/excel/_base.py:798: error: Argument 1 to "len" has incompatible type "Union[int, Sequence[int], None]"; expected "Sized"  [arg-type]
Found 3 errors in 1 file (checked 1391 source files)
``` Thx, fixed thanks @phofl 