Add stake flags struct

[HaoranYi]

Problem

Fix a stake redelegation issue.

Part of #31876

Summary of Changes

Add stake_flag struct

Fixes #

[codecov]

Codecov Report

Merging #32521 (99dd2e1) into master (c69bc00) will increase coverage by 0.0%.
The diff coverage is 72.7%.

@@           Coverage Diff           @@
##           master   #32521   +/-   ##
=======================================
  Coverage    82.0%    82.0%           
=======================================
  Files         779      780    +1     
  Lines      210609   210664   +55     
=======================================
+ Hits       172742   172817   +75     
+ Misses      37867    37847   -20     

[t-nelson]

ah! splitting the other pr into multiple commits would've been fine as well. only really necessary to ease review. namely moving the flag plumbing out on its own so functional changes are clear.

this works too though! 🙏