manual_glidein_submit working only w/ proxy

[mambelli]

Describe the bug
When running manual_glidein_submit on a token only configuration there is a crash:

Traceback (most recent call last):
  File "/usr/bin/manual_glidein_submit", line 247, in <module>
    sys.exit(main())
  File "/usr/bin/manual_glidein_submit", line 165, in main
    proxyid = sym_key_obj.decrypt_hex(ad_gc["GlideinEncParamSubmitProxy"]).decode("utf8")
KeyError: 'GlideinEncParamSubmitProxy'

Looking a the code it seems to require a proxy in the glidein classad.

To Reproduce
Try using the command on a setup w/o a grid proxy, e.g.: manual_glidein_submit --entry-name ITB_FC_CE4 --debug --fe-name vofrontend_service
Where ITB_FC_CE4 requires scitoken and the Frontend uses only scitokens/idtokens.

Expected behavior
Should work and submit the glidein using tokens

Screenshots
NA

Info (please complete the following information):

• GlideinWMS version: 3.9.6 (and previous)
• Python version: 3.6
• OS version: any
• HTCondor version: 9.0.17 from OSG
• Priority: high
• Stakeholder: GWMS
• Component: factory

Additional context
Add any other context or supporting files about the problem here.