Chore: add configurable feature type lifetimes flag (#4253)

Relates to #4205

src/lib/__snapshots__/create-config.test.ts.snap

@@ -71,6 +71,7 @@ exports[`should create default config 1`] = `
       "anonymiseEventLog": false,
       "caseInsensitiveInOperators": false,
       "cleanClientApi": false,
+      "configurableFeatureTypeLifetimes": false,
       "customRootRoles": false,
       "demo": false,
       "disableBulkToggle": false,
@@ -105,6 +106,7 @@ exports[`should create default config 1`] = `
       "anonymiseEventLog": false,
       "caseInsensitiveInOperators": false,
       "cleanClientApi": false,
+      "configurableFeatureTypeLifetimes": false,
       "customRootRoles": false,
       "demo": false,
       "disableBulkToggle": false,

src/lib/types/experimental.ts

@@ -25,7 +25,8 @@ export type IFlagKey =
     | 'strategyVariant'
     | 'newProjectLayout'
     | 'slackAppAddon'
-    | 'emitPotentiallyStaleEvents';
+    | 'emitPotentiallyStaleEvents'
+    | 'configurableFeatureTypeLifetimes';
 
 export type IFlags = Partial<{ [key in IFlagKey]: boolean | Variant }>;
 
@@ -119,6 +120,11 @@ const flags: IFlags = {
         process.env.UNLEASH_EXPERIMENTAL_EMIT_POTENTIALLY_STALE_EVENTS,
         false,
     ),
+
+    configurableFeatureTypeLifetimes: parseEnvVarBoolean(
+        process.env.UNLEASH_EXPERIMENTAL_CONFIGURABLE_FEATURE_TYPE_LIFETIMES,
+        false,
+    ),
 };
 
 export const defaultExperimentalOptions: IExperimentalOptions = {

src/server-dev.ts

@@ -42,6 +42,7 @@ process.nextTick(async () => {
                         newProjectLayout: true,
                         emitPotentiallyStaleEvents: true,
                         slackAppAddon: true,
+                        configurableFeatureTypeLifetimes: true,
                     },
                 },
                 authentication: {