Allow ctrl+d to exit terminal when valid access patterns exist (#150)

We recently introduced `validAccessPatterns` in #147 which checks to
make sure a certain termination string exists when performing
propagation checks. Consequentially for Azure, when we exit the terminal
we're now always attempting to verify that an ephemeral access message
is valid and failing the check.

Two fixes were possible, 1) we either only check `isValidError` if we're
in a propagation check or 2) we default `isValidError` to true and we
only set it to false if we encounter an error.

We didn't go with the first option in #147 because we want to remove the
concept of `isAccessPropagationPreTest` from the
`accessPropagationGuard`, but checking for valid error messages should
only apply during the pretest phase. This PR instead only passes
`validAccessPatterns` if we're performing a pre-test to the propagation
guard.

src/plugins/ssh/index.ts

@@ -32,11 +32,6 @@ import {
 } from "node:child_process";
 import { Readable } from "node:stream";
 
-/** Maximum amount of time after SSH subprocess starts to check for {@link UNPROVISIONED_ACCESS_MESSAGES}
- *  in the process's stderr
- */
-const DEFAULT_VALIDATION_WINDOW_MS = 5e3;
-
 const RETRY_DELAY_MS = 5000;
 
 /** Checks if access has propagated through AWS to the SSM agent
@@ -74,15 +69,15 @@ const accessPropagationGuard = (
       chunkString.match(message.pattern)
     );
 
-    const matchPreTestPattern = validAccessPatterns?.find((message) =>
+    const matchValidAccessPattern = validAccessPatterns?.find((message) =>
       chunkString.match(message.pattern)
     );
 
     if (matchUnprovisionedPattern) {
       isEphemeralAccessDeniedException = true;
     }
 
-    if (matchPreTestPattern && !matchUnprovisionedPattern) {
+    if (matchValidAccessPattern && !matchUnprovisionedPattern) {
       isValidError = true;
     }
 
@@ -190,7 +185,9 @@ async function spawnSshNode(
     // TODO ENG-2284 support login with Google Cloud: currently return a boolean to indicate if the exception was a Google login error.
     const { isAccessPropagated, isLoginException } = accessPropagationGuard(
       provider.unprovisionedAccessPatterns,
-      provider.provisionedAccessPatterns,
+      options.isAccessPropagationPreTest
+        ? provider.provisionedAccessPatterns
+        : undefined,
       provider.loginRequiredPattern,
       child,
       options