various bugfixes around tag processing

[edaniszewski]

This PR:

• fixes a bug around user-specified namespaces for the tags request. in the event that only a single namespace is specified and not wrapped in a list, the tag processing would fail on namespace matching due to a string also being iterable (e.g. the algorithm iterated over the string characters instead of the expected strings in a list)
• fixes a bug in the read command around how tags are passed along to the command handler. with the introduction of tag groups, the number of valid tag formats include:
  • a single string (a single tag)
  • a list of strings (one tag group, multiple tags)
  • a list of list of strings (multiple tag groups)
    the bug affected the second format, above, because the tags input was not normalized prior to processing, so the algorithm tried to iterate over a string instead of a list of string.
• updated / added tests
• bump to 3.0.0-alpha.13

[hoanhan101]

👍