Remove singleDefaultNamespace field from helm chart

[shubham-bansal96]

Description

We have removed singleDefaultNamespace field from helm chart. Fission will work with both default and additional namespace(if values present in additional namespace).

Which issue(s) this PR fixes:

Fixes #

Testing

Checklist:

• I ran tests as well as code linting locally to verify my changes.
• I have done manual verification of my changes, changes working as expected.
• I have added new tests to cover my changes.
• My changes follow contributing guidelines of Fission.
• I have signed all of my commits.

[codecov]

Codecov Report

Merging #2670 (62c7a02) into main (d52c602) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #2670      +/-   ##
==========================================
- Coverage   19.15%   19.14%   -0.02%     
==========================================
  Files          65       65              
  Lines        7209     7209              
==========================================
- Hits         1381     1380       -1     
- Misses       5726     5727       +1     
  Partials      102      102              

Flag	Coverage Δ
unittests	19.14% <ø> (-0.02%)	⬇️

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Impacted Files	Coverage Δ
pkg/utils/serviceaccount.go	0.00% <ø> (ø)
pkg/utils/httpserver/server.go	55.55% <0.00%> (-5.56%)	⬇️

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[sanketsudake]

LGTM