[MM-12452] Stop inserting hashed plugin keys (#9817)

* Stop inserting hashed plugin keys

* Address comments

* Remove else statement

* Address comments

* Add comment

* Update as per comments

* Refactor as per comments

* Update plugin_key_value_store.go

minor comment tweaks

* fail on non StatusNotFound for original key query

* idiomatic error handling, and do not clean up if insert fails

model/plugin_key_value_test.go

@@ -19,4 +19,7 @@ func TestPluginKeyIsValid(t *testing.T) {
 	kv.PluginId = "someid"
 	kv.Key = ""
 	assert.NotNil(t, kv.IsValid())
+
+	kv.Key = "this is an extremely long key and should be invalid and this is being verified in this test"
+	assert.NotNil(t, kv.IsValid())
 }