test: devnet runtime api

[Daanvdplas]

Add tests for runtime/devnet/src/api.

Changes AllowBalancesCall from devnet and testnet to nothing (#132 (comment))

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 48.89%. Comparing base (448cbca) to head (5209c44).
Report is 3 commits behind head on daan/api.

@@             Coverage Diff              @@
##           daan/api     #274      +/-   ##
============================================
+ Coverage     45.92%   48.89%   +2.97%     
============================================
  Files            47       47              
  Lines          4279     4532     +253     
  Branches       4279     4532     +253     
============================================
+ Hits           1965     2216     +251     
- Misses         2252     2254       +2     
  Partials         62       62              

Files with missing lines	Coverage Δ
pallets/api/src/fungibles/mod.rs	85.48% <ø> (+2.70%)	⬆️
runtime/devnet/src/config/api/mod.rs	67.44% <100.00%> (+32.14%)	⬆️
runtime/devnet/src/config/api/versioning.rs	90.60% <100.00%> (+30.60%)	⬆️
runtime/devnet/src/config/contracts.rs	83.33% <100.00%> (+23.33%)	⬆️
runtime/devnet/src/lib.rs	6.44% <100.00%> (ø)
runtime/testnet/src/config/contracts.rs	83.33% <100.00%> (+23.33%)	⬆️
runtime/testnet/src/lib.rs	5.37% <100.00%> (+1.47%)	⬆️

... and 3 files with indirect coverage changes

[evilrobot-01]

Looks good, think there are some easy improvements to make to finish this off.

[chungquantin]

Approved. Would be great to refactor the tests a bit!