feat(scaffolder): implement scaffolderServiceRef for credentials aware communication (#33044)

* add scaffolderServiceRef to scaffolder-node

Signed-off-by: benjdlambert <ben@blam.sh>

* make ScaffolderApi methods required, add tests

Signed-off-by: benjdlambert <ben@blam.sh>

* use request objects for single-string params in ScaffolderService

Signed-off-by: benjdlambert <ben@blam.sh>

* add scaffolderServiceMock test utility

Signed-off-by: benjdlambert <ben@blam.sh>

* adjust review comments

Signed-off-by: benjdlambert <ben@blam.sh>

* add scaffolderApiMock test utility to scaffolder-react

Signed-off-by: benjdlambert <ben@blam.sh>

* use items/totalItems response shape for listTasks

Signed-off-by: benjdlambert <ben@blam.sh>

* pass credentials through for autocomplete

Signed-off-by: benjdlambert <ben@blam.sh>

---------

Signed-off-by: benjdlambert <ben@blam.sh>

plugins/scaffolder-node/package.json

@@ -27,6 +27,7 @@
   "exports": {
     ".": "./src/index.ts",
     "./alpha": "./src/alpha/index.ts",
+    "./testUtils": "./src/testUtils.ts",
     "./package.json": "./package.json"
   },
   "main": "src/index.ts",
@@ -36,6 +37,9 @@
       "alpha": [
         "src/alpha/index.ts"
       ],
+      "testUtils": [
+        "src/testUtils.ts"
+      ],
       "package.json": [
         "package.json"
       ]
@@ -79,6 +83,15 @@
     "@backstage/backend-test-utils": "workspace:^",
     "@backstage/cli": "workspace:^",
     "@backstage/config": "workspace:^",
-    "@types/lodash": "^4.14.151"
+    "@types/lodash": "^4.14.151",
+    "msw": "^1.0.0"
+  },
+  "peerDependencies": {
+    "@backstage/backend-test-utils": "workspace:^"
+  },
+  "peerDependenciesMeta": {
+    "@backstage/backend-test-utils": {
+      "optional": true
+    }
   }
 }