[chore] Reject duplicate deposit requests when first one already accepted | confirmed | failed

[MCJOHN974]

Description

Closes: #1161

Changes

Now create_deposit requests returns 409 (Conflict) if we already have same deposit accepted

Testing Information

Added integration test for this.

Locally I run it the following way:

 docker compose -f docker/docker-compose.test.yml build   // rebuild emily
 docker compose --file docker/docker-compose.test.yml up.  // start emily
 // open new terminal
 cargo test --package emily-handler --test integration -- deposit::overwrite_deposit --exact --show-output --ignored // run the test

Checklist:

• I have performed a self-review of my code
• My changes generate no new warnings
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[MCJOHN974]

@matteojug is it correct that we want to reject deposits not only if they are Accepted, but Confirmed, Failed and Reprocessing as well?

[Jiloc]

Welcome to the Emily side of things @MCJOHN974 ! I left a few comments about changes required to handle duplicates deposits in all statuses

[MCJOHN974]

Thanks @matteojug and @Jiloc for your comments, I think last few commits contain your suggestions