Narrow down shielding retry logic (backport #4071)

[mergify]

Describe your changes

Closes #4045.

Ensures that the retry logic for a failed shielding tx hitting an epoch boundary is applied only when the MASP vp is the only one rejecting the tx and the error is among the expected ones.

Checklist before merging

• If this PR has some consensus breaking changes, I added the corresponding breaking:: labels
  • This will require 2 reviewers to approve the changes
• If this PR requires changes to the docs or specs, a corresponding PR is opened in the namada-docs repo
  • Relevant PR if applies:
• If this PR affects services such as namada-indexer or namada-masp-indexer, a corresponding PR is opened in that repo
  • Relevant PR if applies:

---

This is an automatic backport of pull request #4071 done by [Mergify](https://mergify.com).

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.58%. Comparing base (ad3be9c) to head (421dcd7).
Report is 5 commits behind head on maint-0.46.

Additional details and impacted files

@@             Coverage Diff             @@
##           maint-0.46    #4092   +/-   ##
===========================================
  Coverage       74.58%   74.58%           
===========================================
  Files             341      341           
  Lines          107484   107484           
===========================================
+ Hits            80162    80169    +7     
+ Misses          27322    27315    -7     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.