fix: increase start delay for ASGI conformance tests to address flaky failures

[taeold]

Summary

• Increased startDelay from 1 to 5 seconds for all ASGI conformance test steps
• This matches the configuration used in buildpack integration tests which run reliably

Problem

The ASGI conformance tests are failing sporadically with connection refused errors:

2025/07/24 17:30:27 validation failure: failed to get response from HTTP function: failed to send HTTP request: Post "http://localhost:8080": dial tcp [::1]:8080: connect: connection refused
Server logs: 
[/tmp/ff_serverlog_stdout.txt]: ''
[/tmp/ff_serverlog_stderr.txt]: ''

Hypothesis

The default 1-second start delay may be insufficient for Uvicorn/ASGI server startup in CI environments.

Seems to be more stable w/ this change.