Slow down evm event checking

[MechanicalTyler]

Related Github tickets

• bug: suspicious increase in ethereum RPC requests and eth_getLogs errors paloma#976

Background

This was previously checking every 5 seconds for events to send a token to Paloma. This may be unnecessarily using up RPC calls for pigeons when not much is happening. Slowing this down, which will effectively reduce the call numbers while batching events that may happen together.

Also removed an unused interval accidentally left in

Testing completed

• this is a loop interval, no tests exist or are needed for it
• tested in a private testnet

Breaking changes

• I have checked my code for breaking changes

[byte-bandit]

lgtm

[taariq]

Hold on now. We are slowing down, but what happens when we launch GRAIN and it's trading on EVM and moving back and forth? Well have to cut a new release just to handle new volume?

[MechanicalTyler]

@taariq Yes, that's true. This is basically a slow down so we can rule it out or confirm it as a contributing factor to our current problems relaying.

[taariq]

@ToasterTheBrave Thanks. understdood.

[pegahcarter]

I'm interested to know how the value of 1 minute was decided. Is this an arbitrary constant?

[taariq]

@pegahcarter it's a best guess. the volume of rpc queries on the validator endpoints were hitting millions per month with every five seconds. this change will need to be eventually dynamic and based on the bridge volume for each particular chain level of bridge activity. lots of optimizations to explore. 1 minute was immediate relief without losing the bridge security model.