Fixed multiple send_message calls to work simultaneously

[melatron]

Description of change

1. Removed the block_on pattern in which the tokio runtime was called guarded with a mutex. Currently we spawn tasks for each async call.
2. Removed the mutex which prevented to make simultaneous calls.
3. Changed wallet.rs version, so that we can call handle from multiple tokio tasks simultaneously.
4. Change function arguments in shared/lib/typings/account.ts to match those with the wallet.rs API (specifically this method)

Type of change

• Bug fix (a non-breaking change which fixes an issue)

Change checklist

• I have followed the contribution guidelines for this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes