fix: use experimental for alpha features

Experimental: An early stage "Preview," these features truly are
experiments and might never reach GA.

Longhorn 9794

Signed-off-by: Derek Su <[email protected]>

types/setting.go

@@ -249,7 +249,7 @@ const (
 	SettingCategoryScheduling   = SettingCategory("scheduling")
 	SettingCategoryDangerZone   = SettingCategory("danger Zone")
 	SettingCategorySnapshot     = SettingCategory("snapshot")
-	SettingCategoryV2DataEngine = SettingCategory("v2 data engine (Preview Feature)")
+	SettingCategoryV2DataEngine = SettingCategory("v2 data engine (Experimental Feature)")
 )
 
 type SettingDefinition struct {
@@ -1335,7 +1335,7 @@ var (
 
 	SettingDefinitionV2DataEngine = SettingDefinition{
 		DisplayName: "V2 Data Engine",
-		Description: "This setting allows users to activate v2 data engine which is based on SPDK. Currently, it is in the preview phase and should not be utilized in a production environment.\n\n" +
+		Description: "This setting allows users to activate v2 data engine which is based on SPDK. Currently, it is in the experimental phase and should not be utilized in a production environment.\n\n" +
 			"  - DO NOT CHANGE THIS SETTING WITH ATTACHED VOLUMES. Longhorn will block this setting update when there are attached v2 volumes. \n\n" +
 			"  - When the V2 Data Engine is enabled, each instance-manager pod utilizes 1 CPU core. This high CPU usage is attributed to the spdk_tgt process running within each instance-manager pod. The spdk_tgt process is responsible for handling input/output (IO) operations and requires intensive polling. As a result, it consumes 100% of a dedicated CPU core to efficiently manage and process the IO requests, ensuring optimal performance and responsiveness for storage operations. \n\n",
 		Category: SettingCategoryDangerZone,