TYP: misc fixes for numpy types 2
```
pandas\core\dtypes\cast.py:681: error: Incompatible types in assignment (expression has type "DatetimeTZDtype", variable has type "dtype")  [assignment]
pandas\core\dtypes\cast.py:715: error: Incompatible types in assignment (expression has type "IntervalDtype", variable has type "dtype")  [assignment]
pandas\core\dtypes\common.py:1392: error: Item "dtype" of "Union[dtype, ExtensionDtype]" has no attribute "_is_boolean"  [union-attr]
pandas\core\dtypes\common.py:111: error: Function "numpy.array" is not valid as a type  [valid-type]
pandas\core\reshape\merge.py:1873: error: Function "numpy.array" is not valid as a type  [valid-type]
```
thanks @simonjayhawkins 