Solana: Settler tests refactor

[GuidoDipietro]

Changes Settler unit test pattern to use context() as requested in previous PRs (comes from #50).

[PedroAraoz]

General comments

1. If we are going to always do &[EntityType::Solver as u8 + 1] when using the controller from the settler, I would just change the controller so the enum starts at 0.
2. Follow the testing convention we use, you can use the EVM Settler as reference
3. Extract repeated code into functions
4. Always use helper functions, for example when creating the intent it is sometimes done createTestIntent but not always

Helpers.ts

Leaving this here because GH does not allow commenting on files not changed by the PR

1. I would split it into multiple files
2. I would split createTestIntent into one function that creates the data (like we use in the backend repo) and maybe another that sends the ix and returns the hash

[GuidoDipietro]

Feedback about your earlier message @PedroAraoz:

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1. If we are going to always do &[EntityType::Solver as u8 + 1] when using the controller from the settler, I would just change the controller so the enum starts at 0.

Granted. Changed

2. Follow the testing convention we use, you can use the EVM Settler as reference

Modified tests to follow that convention better, still unsure if they are properly formatted

3. Extract repeated code into functions

Did this with everything I could, let me know if you see anything I missed

4. Always use helper functions, for example when creating the intent it is sometimes done createTestIntent but not always

Tried to fix that as well, again let me know if I missed anything

1. I would split it (helpers.ts) into multiple files

I split this into several files now, grouping functionality together

2. I would split createTestIntent into one function that creates the data (like we use in the backend repo) and maybe another that sends the ix and returns the hash

Makes sense, done.

[GuidoDipietro]

NOTE: The add_axia_sig and add_validator_sig tests still have logic on the it, but I'm refactoring them on a new PR given the logic in them will change as well.