Simplify provider name shortening

Instead of using a regular expression to parse
the name, we try to find the provider name inside
the already existing constant that knows providers
short names.

modules/storages/app/models/storages/storage.rb

@@ -92,14 +92,12 @@ class Storage < ApplicationRecord
     }.freeze, _prefix: :health
 
     def self.shorten_provider_type(provider_type)
-      case /Storages::(?'provider_name'.*)Storage/.match(provider_type)
-      in provider_name:
-        provider_name.underscore
-      else
-        raise ArgumentError,
-              "Unknown provider_type! Given: #{provider_type}. " \
-              "Expected the following signature: Storages::{Name of the provider}Storage"
-      end
+      short, = PROVIDER_TYPE_SHORT_NAMES.find { |_, long| provider_type == long }
+      return short.to_s if short
+
+      raise ArgumentError,
+            "Unknown provider_type! Given: #{provider_type}. " \
+            "Known provider types are defined in Storages::Storage::PROVIDER_TYPE_SHORT_NAMES."
     end
 
     def self.one_drive_without_ee_token?(provider_type)

modules/storages/spec/models/storages/shared_base_storage_spec.rb

@@ -49,20 +49,24 @@
       end
     end
 
-    context "when provider_type does not match the signature" do
+    context "when provider_type is unknown" do
       it "raises an error", :aggregate_failures do
         expect do
           described_class.shorten_provider_type("Storages::Nextcloud")
         end.to raise_error("Unknown provider_type! Given: Storages::Nextcloud. " \
-                           "Expected the following signature: Storages::{Name of the provider}Storage")
+                           "Known provider types are defined in Storages::Storage::PROVIDER_TYPE_SHORT_NAMES.")
         expect do
           described_class.shorten_provider_type("Storages:NextcloudStorage")
         end.to raise_error("Unknown provider_type! Given: Storages:NextcloudStorage. " \
-                           "Expected the following signature: Storages::{Name of the provider}Storage")
+                           "Known provider types are defined in Storages::Storage::PROVIDER_TYPE_SHORT_NAMES.")
         expect do
           described_class.shorten_provider_type("Storages::NextcloudStorag")
         end.to raise_error("Unknown provider_type! Given: Storages::NextcloudStorag. " \
-                           "Expected the following signature: Storages::{Name of the provider}Storage")
+                           "Known provider types are defined in Storages::Storage::PROVIDER_TYPE_SHORT_NAMES.")
+        expect do
+          described_class.shorten_provider_type("Storages::UnknownStorage")
+        end.to raise_error("Unknown provider_type! Given: Storages::UnknownStorage. " \
+                           "Known provider types are defined in Storages::Storage::PROVIDER_TYPE_SHORT_NAMES.")
       end
     end
   end