astropy: Possible Bug? `parse_single_table` lose dtype info for `char(*)` type.

Description

With a VOTable like:

<?xml version="1.0" encoding="utf-8"?>
<!-- Produced with astropy.io.votable version 5.1
     http://www.astropy.org/ -->
<VOTABLE version="1.4" xmlns="http://www.ivoa.net/xml/VOTable/v1.3" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.ivoa.net/xml/VOTable/v1.3 http://www.ivoa.net/xml/VOTable/VOTable-1.4.xsd">
 <RESOURCE type="results">
   ...
   <FIELD ID="original_ext_source_id" arraysize="80" datatype="char" name="original_ext_source_id" ucd="meta.id.cross"/>
   ...
   <DATA>
    <TABLEDATA>
     ...

The field original_ext_source_id is of type char[80]

running:

>>> from astropy.io.votable import parse_single_table
>>> table = parse_single_table(<filename>)
>>> for row in table.array:
        print(type(row))
        for cell in row:
           print(type(cell))
           print(cell.dtype)
             
<class 'numpy.ma.core.mvoid'>
<class 'numpy.int64'>
int64
<class 'str'>
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Cell In[24], line 5
      3 for cell in row:
      4     print(type(cell))
----> 5     print(cell.dtype)

AttributeError: 'str' object has no attribute 'dtype'

The cell object is a builtin python string and the dtype information got lost.

Expected behavior

I would expect the same behavior as with unicodeChar type:

with the following VOTable file:

<?xml version="1.0" encoding="utf-8"?>
<!-- Produced with astropy.io.votable version 5.1
     http://www.astropy.org/ -->
<VOTABLE version="1.4" xmlns="http://www.ivoa.net/xml/VOTable/v1.3" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.ivoa.net/xml/VOTable/v1.3 http://www.ivoa.net/xml/VOTable/VOTable-1.4.xsd">
 <RESOURCE type="results">
   ...
   <FIELD ID="original_ext_source_id" arraysize="80" datatype="unicodeChar" name="original_ext_source_id" ucd="meta.id.cross"/>
   ...
   <DATA>
    <TABLEDATA>
     ...

The field original_ext_source_id is now of type unicodeChar[80]

running:

>>> from astropy.io.votable import parse_single_table
>>> table = parse_single_table(<filename>)
>>> for row in table.array:
        print(type(row))
        for cell in row:
           print(type(cell))
           print(cell.dtype)
<class 'numpy.ma.core.mvoid'>
<class 'numpy.int64'>
int64
<class 'numpy.str_'>
<U80

In this case the cell object is a numpy string and the dtype information is available.

How to Reproduce

1. Get package from ‘…’
2. Then run ‘…’
3. An error occurs.

>>> from astropy.io.votable import parse_single_table
>>> table = parse_single_table(<filename>)
>>> for row in table.array:
        print(type(row))
        for cell in row:
           print(type(cell))
           print(cell.dtype)
             
<class 'numpy.ma.core.mvoid'>
<class 'numpy.int64'>
int64
<class 'str'>
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Cell In[24], line 5
      3 for cell in row:
      4     print(type(cell))
----> 5     print(cell.dtype)

AttributeError: 'str' object has no attribute 'dtype'

Versions

Linux-4.19.0-9-amd64-x86_64-with-glibc2.28
Python 3.9.13+ (heads/3.9:e8f2fe355b, Jun 13 2022, 10:51:14) 
[GCC 8.3.0]
astropy 5.1
Numpy 1.22.4
pyerfa 2.0.0.1

no scipy and no matplotlib