fix: Make from_template_and_variables async for backwards compatibility, add sync version, add tests and small fixes

[ogabrielluiz]

This pull request includes several updates to improve the handling of session IDs and prompt message construction across various components. The most important changes include adding checks for session IDs, updating prompt message construction methods, and modifying starter project templates.

Session ID Handling Improvements:

• src/backend/base/langflow/base/agents/agent.py: Added checks for graph and _session_id attributes to set session_id in the run_agent method.
• src/backend/base/langflow/custom/custom_component/component.py: Added similar checks for graph and _session_id attributes to set session_id in the build_results method.

Prompt Message Construction:

• src/backend/base/langflow/components/prompts/prompt.py: Updated build_prompt method to use Message.from_template instead of Message.from_template_and_variables.

Starter Project Template Updates:

• Updated multiple starter project JSON files to reflect changes in prompt message construction:
  • Basic Prompting (Hello, World).json (src/backend/base/langflow/initial_setup/starter_projects/Basic Prompting (Hello, World).jsonL426-R426)
  • Blog Writer.json
  • Complex Agent.json [1] [2]

Other Code Improvements:

• src/backend/base/langflow/custom/custom_component/custom_component.py: Updated trace_name property to use _id instead of _vertex.id.

[codspeed-hq]

CodSpeed Performance Report

Merging #4500 will degrade performances by 17%

_{Comparing prompt-tests-backwards (0a55bc6) with main (8bb0f65)}

Summary

❌ 2 regressions
✅ 13 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	prompt-tests-backwards	Change
❌	test_successful_run_with_input_type_text	455.7 ms	532.6 ms	-14.43%
❌	test_successful_run_with_output_type_any	378 ms	455.4 ms	-17%

[edwinjosechittilappilly]

LGTM