Improve agent creation flow

[EugeneLightsOn]

Create deployments and models during the agent creation flow if they are not present in the database but have configurations in the codebase.

AI Description

This PR introduces new functions and updates existing ones to enhance the deployment and model management system.

• New Functions:

  • find_config_by_deployment_id and find_config_by_deployment_name in src/backend/config/deployments.py enable configuration retrieval by deployment ID or name.
  • create_deployment_by_config in src/backend/crud/deployment.py facilitates deployment creation from a configuration.
  • get_model_by_name in src/backend/crud/model.py retrieves a model by its name.
  • create_model_by_config in src/backend/crud/model.py creates a new model based on a configuration.

• Updated Functions:

  • validate_deployment_model in src/backend/services/request_validators.py now checks deployment config settings and creates deployments and models if they are not found.
  • test_create_agent_deployment_not_in_db in src/backend/tests/unit/routers/test_agent.py tests agent creation with a deployment not in the database.
  • test_streaming_chat_with_tools_not_in_agent_tools and test_streaming_chat_with_agent_tools_and_empty_request_tools in src/backend/tests/unit/routers/test_chat.py have been updated to use the "tavily_web_search" tool.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 58.82353% with 28 lines in your changes missing coverage. Please review.

Project coverage is 79.68%. Comparing base (547827f) to head (938d69a).

Files with missing lines	Patch %	Lines
src/backend/tests/unit/routers/test_agent.py	37.50%	10 Missing ⚠️
src/backend/crud/model.py	52.94%	8 Missing ⚠️
src/backend/crud/deployment.py	50.00%	5 Missing ⚠️
src/backend/tests/unit/routers/test_chat.py	0.00%	3 Missing ⚠️
src/backend/config/deployments.py	90.00%	1 Missing ⚠️
src/backend/services/request_validators.py	90.90%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #814      +/-   ##
==========================================
- Coverage   79.80%   79.68%   -0.12%     
==========================================
  Files         243      243              
  Lines       10355    10417      +62     
==========================================
+ Hits         8264     8301      +37     
- Misses       2091     2116      +25     

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[tianjing-li]

Small change requested