Do not enable BETA launch-stage for referencing secrets

As referencing Secret Manager secrets has moved to GA. See:
https://cloud.google.com/run/docs/release-notes#November_09_2021

locals.tf

@@ -39,12 +39,6 @@ locals {
     load-balancer = "internal-and-cloud-load-balancing"
   }, var.ingress_style, var.allowed_ingress)
 
-  # Do we need to enable the 'beta' launch stage - only required if certain beta
-  # functionality is being used, or if `enable_beta_launch_stage` is set downstream.
-  enable_beta_launch_stage = (
-    var.enable_beta_launch_stage || length(var.secrets_volume) != 0 || length(var.secrets_envars) != 0
-  )
-
   # Whether we should monitor the custom domain - only possible if there are a dns names
   # set and unauthenticated invocation is enabled.
   can_monitor_custom_dns = length(local.dns_names) > 0 && var.allow_unauthenticated_invocations

main.tf

@@ -44,7 +44,7 @@ resource "google_cloud_run_service" "webapp" {
       },
 
       # Add the beta launch stage if required.
-      local.enable_beta_launch_stage ? {
+      var.enable_beta_launch_stage ? {
         # Required to be able to set ingress type and secrets volume mounts
         "run.googleapis.com/launch-stage" : "BETA",
       } : {},
@@ -184,7 +184,7 @@ resource "google_cloud_run_service" "webapp" {
       # These are only changed when "run.googleapis.com/launch-stage" is "BETA".
       # It's non-trivial to make ignore_changes dependent on input variables so
       # we always ignore these annotations even if, strictly speaking, we only
-      # need to do so is local.enable_beta_launch_stage is true.
+      # need to do so is var.enable_beta_launch_stage is true.
       metadata[0].annotations["serving.knative.dev/creator"],
       metadata[0].annotations["serving.knative.dev/lastModifier"],