fix(block-replacer): update test to reflect preloaded-content behavior

When both srcPath and content are provided, content is now used as
preloaded file contents instead of throwing an error. Update the test
to match the new intentional behavior.

Co-authored-by: David Wells <DavidWells@users.noreply.github.com>

Author: github-actions[bot]

packages/block-replacer/test/index.test.js

@@ -192,20 +192,18 @@ test content
   assert.is(result.isChanged, false)
 })
 
-test('should handle both srcPath and content error', async () => {
+test('should handle both srcPath and content using preloaded content', async () => {
   /** @type {ProcessFileOptions} */
   const options = {
-    srcPath: '/some/path',
-    content: 'some content',
+    srcPath: '/some/nonexistent/path',
+    content: 'preloaded content',
     dryRun: true
   }
 
-  try {
-    await processFile(options)
-    assert.unreachable('Should have thrown an error')
-  } catch (error) {
-    assert.ok(error.message.includes('Can\'t set both "srcPath" & "content"'))
-  }
+  // When both srcPath and content are provided, content is used as preloaded
+  // file contents (caching optimization) — no error should be thrown.
+  const result = await processFile(options)
+  assert.ok(result, 'Should return a result without throwing')
 })
 
 test('should handle file with output directory', async () => {