read_excel na_values replacement after parse_dates
```python
### Not working
pd.read_excel(
    "test.xlsx",
    na_values={"Test": ['#', 0]},
    parse_dates=["Test"],
    date_parser=lambda x: pd.to_datetime(x, format="%Y-%m-%d"),
)
### Working
pd.read_csv(
    "test.txt",
    na_values={"Test": ['#', 0]},
    parse_dates=["Test"],
    date_parser=lambda x: pd.to_datetime(x, format="%Y-%m-%d"),
)

```
read_excel behaves different from read_csv in replacing NA values and parsing dates.

Test case:
The test.txt and test.xlsx contain the same data, just one column with header "Test" and 5 entries where 0 and # both represent NA values.
```
Test
2012-10-01
0
2015-05-15
#
2017-09-09
```
The first one crashes while trying to parse a "#" character as date.