Fix view tracking on sharded keyspace

[harshit-gangal]

Description

When vtgate receives SELECT * queries and possesses authoritative column information for the tables in the query, it expands * into the actual column list, simplifying subsequent planning.

This column information is sourced from the schema tracker, which experiences a slight delay in reflecting schema changes in vtgate. Previously, following an ALTER TABLE that modified the column list, an immediate ALTER VIEW incorporating a SELECT * led vtgate to expand the columns using outdated information from the schema tracker, causing the resultant view to misrepresent the updated schema.

The remedy involves refraining from expanding columns in CREATE/ALTER VIEW statements, allowing MySQL to handle column expansion. The schema tracker then forwards the view definition to vtgate, ensuring consistency.

However, a temporal lag may persist; if a view is queried immediately post-alteration, it might display the previous definition until vtgate receives the updated information. Unlike before, where the view would permanently display an incorrect definition, this issue is now transient.

Related Issue(s)

Fixes #15456

Checklist

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 65.64%. Comparing base (4c70c7e) to head (1a19f89).
Report is 8 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #15436   +/-   ##
=======================================
  Coverage   65.64%   65.64%           
=======================================
  Files        1562     1563    +1     
  Lines      194318   194370   +52     
=======================================
+ Hits       127553   127589   +36     
- Misses      66765    66781   +16     

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[GuptaManan100]

rest lgtm