BUG: DTI.searchsorted accepting invalid types/dtypes
Analogous to #30763 which fixed the same issue for PeriodIndex.  After this will be a PR to fix TimedeltaIndex, then one to move the fixes up to the EA methods (and share searchsorted).
If a plain `list` is passed should there be an attempt to infer the dtype (or just coerce to an array-like) to determine if the `list` is valid?  E.g. should the following succeed?
```python
In [1]: import pandas as pd; pd.__version__
Out[1]: '0.26.0.dev0+1685.g9565b5666'

In [2]: dti = pd.date_range("2020", periods=3)

In [3]: dti.searchsorted(list(dti))
---------------------------------------------------------------------------
TypeError: searchsorted requires compatible dtype or scalar, not list
``` > If a plain `list` is passed should there be an attempt to infer the dtype (or just coerce to an array-like) to determine if the `list` is valid? E.g. should the following succeed?
> 
> ```python
> In [1]: import pandas as pd; pd.__version__
> Out[1]: '0.26.0.dev0+1685.g9565b5666'
> 
> In [2]: dti = pd.date_range("2020", periods=3)
> 
> In [3]: dti.searchsorted(list(dti))
> ---------------------------------------------------------------------------
> TypeError: searchsorted requires compatible dtype or scalar, not list
> ```

i suppose we could wrap list-likes with pa.array, but this would be an enhancement; can you open an issue. thanks @jbrockmendel 