Fix CI issues: lint, type checker, and test failures

- Remove unused imports from test and example files
- Fix f-string formatting in examples
- Add proper type handling for Union[str, Dict] in agent_utils.py
- Fix XML parser test assertion to match expected output
- Use isinstance() for proper type narrowing in LLM calls

Co-Authored-By: João <joao@crewai.com>

examples/llm_generations_example.py

@@ -2,8 +2,8 @@
 Example demonstrating the new LLM generations and logprobs functionality.
 """
 
-from crewai import Agent, Task, Crew, LLM
-from crewai.utilities.xml_parser import extract_xml_content, extract_multiple_xml_tags
+from crewai import Agent, Task, LLM
+from crewai.utilities.xml_parser import extract_xml_content
 
 
 def example_multiple_generations():
@@ -133,7 +133,7 @@ def example_logprobs_analysis():
             print(f"Available logprobs data: {len(logprobs)} choices")
             
         if usage:
-            print(f"\nToken usage:")
+            print("\nToken usage:")
             print(f"Prompt tokens: {usage.get('prompt_tokens', 'N/A')}")
             print(f"Completion tokens: {usage.get('completion_tokens', 'N/A')}")
             print(f"Total tokens: {usage.get('total_tokens', 'N/A')}")