feat: store the latest StarkNet block hash and number

[jbcaron]

Add tracking for StarkNet's highest block hash and number

This enhancement allows for real-time tracking of the StarkNet chain state, ensuring components have access to the most recent block info.

Pull Request type

Please add the labels corresponding to the type of changes your PR introduces:

• Bugfix
• Feature

What is the current behavior?

Resolves: #NA

What is the new behavior?

• Implement a global, thread-safe variable using lazy_static to store the latest StarkNet block hash and number.
• Add update_highest_block_hash_and_number async function to fetch and update the highest block information from the SequencerGatewayProvider.
• Provide a get_highest_block_hash_and_number function to access the current highest block hash and number safely.

Does this introduce a breaking change?

No

Other information