chore: Fix spelling

Merge https://github.com/google/adk-python/pull/2447

This PR corrects misspellings identified by the [check-spelling action](https://github.com/marketplace/actions/check-spelling)

The misspellings have been reported at https://github.com/jsoref/adk-python/actions/runs/16840838898/attempts/1#summary-47711379253

The action reports that the changes in this PR would make it happy: https://github.com/jsoref/adk-python/actions/runs/16840839269/attempts/1#summary-47711380479

Note: while I use tooling to identify errors, the tooling doesn't _actually_ provide the corrections, I'm picking them on my own. I'm a human, and I may make mistakes.

I've included a couple of changes to make CI happy. Personally, I object to CI being in a state of "random drive by person who adds a blank line in the middle of a file must fix all the preexisting bugs in the file", but that appears to be the state for this repository.

COPYBARA_INTEGRATE_REVIEW=https://github.com/google/adk-python/pull/2447 from jsoref:spelling d85398e7fd154d124d477c6af6181481a01f34e0
PiperOrigin-RevId: 827629615

tests/unittests/tools/test_gemini_schema_util.py

@@ -200,7 +200,7 @@ class TestToGeminiSchema:
         },
     }
     gemini_schema = _to_gemini_schema(openapi_schema)
-    # Since metadata is not properties nor item, it will call to_gemini_schema recursively.
+    # Since metadata is neither properties nor item, it will call to_gemini_schema recursively.
     assert isinstance(gemini_schema.properties["metadata"], Schema)
     assert (
         gemini_schema.properties["metadata"].type == Type.OBJECT
@@ -544,7 +544,7 @@ class TestToGeminiSchema:
         "properties": {
             "case_id": {
                 "description": "The ID of the case.",
-                "title": "Case Id",
+                "title": "Case ID",
                 "type": "string",
             },
             "next_page_token": {
@@ -567,7 +567,7 @@ class TestToGeminiSchema:
         "properties": {
             "case_id": {
                 "description": "The ID of the case.",
-                "title": "Case Id",
+                "title": "Case ID",
                 "type": "string",
             },
             "next_page_token": {