Fix scheduler storage version

[Neopallium]

changelog

data migration

• Remove unneeded migrations and fix pallet_scheduler StorageVersion.

[codecov[bot]]

Codecov Report

Merging #1480 (7e4d46e) into testnet (f530505) will decrease coverage by 0.03%. The diff coverage is 0.00%.

@@             Coverage Diff             @@
##           testnet    #1480      +/-   ##
===========================================
- Coverage    53.88%   53.85%   -0.03%     
===========================================
  Files          146      146              
  Lines        31859    31870      +11     
===========================================
- Hits         17166    17164       -2     
- Misses       14693    14706      +13     

Impacted Files	Coverage Δ
pallets/runtime/common/src/runtime.rs	1.75% <0.00%> (-0.05%)	:arrow_down:
pallets/runtime/develop/src/runtime.rs	3.65% <ø> (ø)

... and 2 files with indirect coverage changes

[Neopallium]

TODO:

• [x] Test migrations.