Fix pwn constgrep when it matches a non-constant type (Fixes #2344)

[disconnect3d]

This commit fixes #2344 - the following issue:

root@pwndbg:~# pwn constgrep a
Traceback (most recent call last):
  File "/usr/local/bin/pwn", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.10/dist-packages/pwnlib/commandline/main.py", line 58, in main
    commands[args.command](args)
  File "/usr/local/lib/python3.10/dist-packages/pwnlib/commandline/constgrep.py", line 110, in main
    for _, k in sorted(out):
TypeError: '<' not supported between instances of 'Constant' and 'type'

Note that it was caused because of the following type object being matched and fetched from the module object:

ipdb> out[25:27]
[(Constant('CS', 0xd), 'CS'), (<class 'pwnlib.constants.constant.Constant'>, 'Constant')]
ipdb> sorted(out[24:27])
*** TypeError: '<' not supported between instances of 'type' and 'Constant'

[disconnect3d]

Note pwn constgrep C would also fail for the same reason. I added a test to CI for this.

[peace-maker]

Good catch