changesets: added changesets for frontend-test-utils api mock changes

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

.changeset/beige-crabs-share.md

@@ -0,0 +1,5 @@
+---
+'@backstage/frontend-test-utils': minor
+---
+
+**BREAKING**: Removed the `TestApiRegistry` class, use `TestApiProvider` directory instead, storing resused APIs in an a variable instead, e.g. `const apis = [...] as const`.

.changeset/catalog-react-catalog-api-mock-shorthand.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-catalog-react': patch
+---
+
+The `catalogApiMock` test utility now returns a `MockWithApiFactory`, allowing it to be passed directly to test utilities like `renderTestApp` and `TestApiProvider` without needing the `[catalogApiRef, catalogApiMock()]` tuple.

.changeset/frontend-test-utils-mock-apis-and-shorthand.md

@@ -0,0 +1,19 @@
+---
+'@backstage/frontend-test-utils': patch
+---
+
+Added a new `mockApis` namespace with mock implementations of many core APIs. Mock API instances can be passed directly to `TestApiProvider`, `renderInTestApp`, and `renderTestApp` without needing `[apiRef, impl]` tuples.
+
+```tsx
+// Before
+import { mockApis } from '@backstage/frontend-test-utils';
+
+renderInTestApp(<MyComponent />, {
+  apis: [[identityApiRef, mockApis.identity()]],
+});
+
+// After - mock APIs can be passed directly
+renderInTestApp(<MyComponent />, {
+  apis: [mockApis.identity()],
+});
+```