fix(features): remove the improved performance enumer (#9819)

# Which Problems Are Solved

Instance that had improved performance flags set, got event errors when
getting instance features. This is because the improved performance
flags were marshalled using the enumerated integers, but now needed to
be unmashalled using the added UnmarshallText method.

# How the Problems Are Solved

- Remove emnumer generation

# Additional Changes

- none

# Additional Context

- reported on QA
- Backport to next-rc / v3

(cherry picked from commit 0465d5093e)

internal/feature/feature.go

@@ -57,7 +57,8 @@ type Features struct {
 	ConsoleUseV2UserApi             bool                      `json:"console_use_v2_user_api,omitempty"`
 }
 
-//go:generate enumer -type ImprovedPerformanceType -trimprefix ImprovedPerformanceType -text
+/* Note: do not generate the stringer or enumer for this type, is it breaks existing events */
+
 type ImprovedPerformanceType int32
 
 const (