Fix: modify transfer widget and write automated test script

[FrankLi123]

No description provided.

[FrankLi123]

This PR mainly focus on:

Modifying transfer widget:

• Fix styling issues
• Display account balances and estimated gas fees for the transaction
• Support Ethereum native and ERC-20 token transactions

Restructuring OpenAgent Test directories to enable:

• Run multiple test files all at once, with specified model name as an argument
• Run individual test files with specified model name as an argument

[FrankLi123]

Commands to run the test cases:

Run a Single Test File with a Specified Model Name:

python tests/run_tests.py gpt-3.5-turbo tests.agent_trajectory.asset_management

Run All Test Files in agent_trajectory with a Specified Model Name:

python tests/run_tests.py gpt-3.5-turbo