[CSUB-874] Update bag thresholds

[nathanwhit]

Description of proposed changes

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Practical tips for PR review & merge:

• All GitHub Actions report PASS
• Newly added code/functions have unit tests
  • Coverage tools report all newly added lines as covered
  • The positive scenario is exercised
  • Negative scenarios are exercised, e.g. assert on all possible errors
  • Assert on events triggered if applicable
  • Assert on changes made to storage if applicable
• Modified behavior/functions - try to make sure above test items are covered
• Integration tests are added if applicable/needed

[codecov-commenter]

Codecov Report

Merging #1383 (debeb40) into dev (d9373cd) will decrease coverage by 0.15%.
The diff coverage is 3.33%.

@@            Coverage Diff             @@
##              dev    #1383      +/-   ##
==========================================
- Coverage   72.00%   71.86%   -0.15%     
==========================================
  Files         110      111       +1     
  Lines       12926    12953      +27     
  Branches      128      128              
==========================================
+ Hits         9308     9309       +1     
- Misses       3608     3634      +26     
  Partials       10       10              

Files	Coverage Δ
runtime/src/version.rs	0.00% <ø> (ø)
runtime/src/lib.rs	16.77% <0.00%> (-0.46%)	⬇️
runtime/generate-bags/src/main.rs	5.26% <5.26%> (ø)

... and 2 files with indirect coverage changes

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[AdaJane]

@nathanwhit Can you summarize the expected impact on the existing nominators? What happens when we release this update?

[github-actions]

For full LLVM coverage report click here!

[nathanwhit]

@nathanwhit Can you summarize the expected impact on the existing nominators? What happens when we release this update?

The existing nominators will be partitioned into the new bags via the migration that runs on the runtime upgrade. I've simulated it on a local network to make sure that it behaves as expected, and that it completes in a reasonable amount of time (I tested with ~30000 nominators and it didn't impact block time or anything).

[atodorov]

Rebased. LGTM.