Fix health check (#428)

* check l2 client health in background worker first

* fix

* removed unused

* logging

* put sleep at end

* fix

* add l2 client unsafe interval test

* chore: specify serial_test version

---------

Co-authored-by: Eric Woolsey <[email protected]>

Author: karankurbur

Cargo.lock

@@ -70,6 +70,7 @@ bytes = "1.10.1"
 lru = "0.16"
 
 [dev-dependencies]
+serial_test = "3"
 rand = "0.9.0"
 time = { version = "0.3.36", features = ["macros", "formatting", "parsing"] }
 op-alloy-consensus.workspace = true