Completely remove "grpc-plugin" as storage type

[yurishkuro]

Which problem is this PR solving?

• Last part of [deprecation] Phase out grpc-plugin storage (sidecar via hashicorp-plugin) #4647
• In accordance with our deprecation policy, this CLI value can be removed in v1.60 (next release)

Description of the changes

• No longer accept grpc-plugin as a storage type. The valid value is grpc.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.89%. Comparing base (e3e763c) to head (3e95bea).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5741      +/-   ##
==========================================
+ Coverage   96.84%   96.89%   +0.04%     
==========================================
  Files         335      335              
  Lines       16166    16160       -6     
==========================================
+ Hits        15656    15658       +2     
+ Misses        340      334       -6     
+ Partials      170      168       -2     

Flag	Coverage Δ
badger_v1	8.05% <ø> (+<0.01%)	⬆️
badger_v2	?
cassandra-3.x-v1	16.61% <ø> (+0.01%)	⬆️
cassandra-3.x-v2	1.82% <ø> (+<0.01%)	⬆️
cassandra-4.x-v1	16.61% <ø> (+0.01%)	⬆️
cassandra-4.x-v2	?
elasticsearch-6.x-v1	18.79% <ø> (+0.01%)	⬆️
elasticsearch-7.x-v1	18.85% <ø> (+0.02%)	⬆️
elasticsearch-8.x-v1	19.03% <ø> (+<0.01%)	⬆️
elasticsearch-8.x-v2	1.90% <ø> (+<0.01%)	⬆️
grpc_v1	9.51% <ø> (-0.01%)	⬇️
grpc_v2	?
kafka	9.74% <ø> (+<0.01%)	⬆️
opensearch-1.x-v1	18.90% <ø> (+0.01%)	⬆️
opensearch-2.x-v1	18.90% <ø> (+0.01%)	⬆️
opensearch-2.x-v2	1.90% <ø> (+0.01%)	⬆️
unittests	95.28% <ø> (+0.04%)	⬆️

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