fix: address flaky tests (#3363)

fix: resolve flaky tests and race conditions in test suite

- Fix telemetry/event tests by patching class methods instead of instances
- Use unique temp files/directories to prevent CI race conditions
- Reset singleton state between tests
- Mock embedchain.Client.setup() to prevent JSON corruption
- Rename test files to test_*.py convention
- Move agent tests to tests/agents directory
- Fix repeated tool usage detection
- Remove database-dependent tools causing initialization errors

tests/agents/agent_builder/test_base_agent.py

@@ -0,0 +1,35 @@
+import hashlib
+from typing import Any, List, Optional
+
+from pydantic import BaseModel
+
+from crewai.agents.agent_builder.base_agent import BaseAgent
+from crewai.tools.base_tool import BaseTool
+
+
+class MockAgent(BaseAgent):
+    def execute_task(
+        self,
+        task: Any,
+        context: Optional[str] = None,
+        tools: Optional[List[BaseTool]] = None,
+    ) -> str:
+        return ""
+
+    def create_agent_executor(self, tools=None) -> None: ...
+
+    def get_delegation_tools(self, agents: List["BaseAgent"]): ...
+
+    def get_output_converter(
+        self, llm: Any, text: str, model: type[BaseModel] | None, instructions: str
+    ): ...
+
+
+def test_key():
+    agent = MockAgent(
+        role="test role",
+        goal="test goal",
+        backstory="test backstory",
+    )
+    hash = hashlib.md5("test role|test goal|test backstory".encode()).hexdigest()
+    assert agent.key == hash