chore!: rename to ValidateBlobNamespace

[rootulp]

Closes #1849

[codecov-commenter]

Codecov Report

Merging #1850 (06de611) into main (1e60076) will decrease coverage by 29.72%.
The diff coverage is 11.15%.

@@             Coverage Diff             @@
##             main    #1850       +/-   ##
===========================================
- Coverage   51.54%   21.82%   -29.72%     
===========================================
  Files          95      116       +21     
  Lines        6220    13247     +7027     
===========================================
- Hits         3206     2891      -315     
- Misses       2671    10065     +7394     
+ Partials      343      291       -52     

Impacted Files	Coverage Δ
app/app.go	4.48% <0.00%> (-0.05%)	⬇️
app/default_overrides.go	23.37% <0.00%> (ø)
app/prepare_proposal.go	0.00% <0.00%> (ø)
app/process_proposal.go	0.00% <0.00%> (ø)
app/square_size.go	0.00% <0.00%> (ø)
pkg/proof/querier.go	21.50% <ø> (ø)
test/util/testnode/full_node.go	0.00% <0.00%> (-83.88%)	⬇️
test/util/testnode/genesis_options.go	0.00% <0.00%> (ø)
test/util/testnode/node_interaction_api.go	0.00% <0.00%> (-57.53%)	⬇️
x/blob/types/params.pb.go	1.27% <0.00%> (ø)
... and 24 more

... and 37 files with indirect coverage changes