Fix Telemetry 1.x warning caused by local function capture

[nallwhy]

This PR fixes the warning from telemetry below.

Function passed as a handler with ID {TelemetryMetricsAppsignal, [:worker], #PID<0.1478.0>} is local function.
This mean that it is either anonymous function or capture of function without module specified. That may cause performance penalty when calling such handler. For more details see note in `telemetry:attach/4` documentation.

https://hexdocs.pm/telemetry/telemetry.html#attach-4

[kamilkowalski]

Great catch @nallwhy! 👏