Fix cache versioning of empty `Op.__props__`

[brandonwillard]

This PR closes #1101 by fixing the way C cache version tuples are generated when Op.__props__ is empty. More specifically, these changes prevent the addition of empty tuples to the C cache version tuples, because empty entries in a C cache version tuple indicate that an Op is un-versionable and cannot be cached.

[codecov[bot]]

Codecov Report

Merging #1108 (3ebb9e5) into main (2dc7591) will decrease coverage by 0.00%. The diff coverage is 63.93%.

@@            Coverage Diff             @@
##             main    #1108      +/-   ##
==========================================
- Coverage   79.28%   79.28%   -0.01%     
==========================================
  Files         152      151       -1     
  Lines       48026    47999      -27     
  Branches    10926    10921       -5     
==========================================
- Hits        38077    38055      -22     
+ Misses       7452     7441      -11     
- Partials     2497     2503       +6     

Impacted Files	Coverage Δ
aesara/link/c/cmodule.py	54.29% <23.80%> (-0.05%)	:arrow_down:
aesara/link/c/op.py	60.95% <78.26%> (-0.09%)	:arrow_down:
aesara/link/c/basic.py	87.57% <93.33%> (+0.20%)	:arrow_up:
aesara/link/c/interface.py	94.18% <100.00%> (+0.13%)	:arrow_up:
aesara/link/c/cutils.py	28.88% <0.00%> (-40.00%)	:arrow_down:
aesara/link/c/type.py	76.41% <0.00%> (+0.43%)	:arrow_up: