Anchor exhausted-retry pattern to a single line to avoid cross-message false positives

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Author: Copilot

actions/setup/js/detect_agent_errors.cjs

@@ -174,7 +174,7 @@ const MISSING_MODEL_PRICING_PATTERN = /Model\s+"([^"]+)"\s+has no AI credits pri
 // All forms are treated as non-retryable; the Copilot CLI/SDK has already retried
 // internally before surfacing this error (evidenced by "retried N times" context).
 const CAPI_QUOTA_EXCEEDED_PATTERN =
-  /CAPIError:\s*(?:429\s+)?(?:429\s+quota exceeded|Too Many Requests)|Failed to get response from the AI model;\s*retried\s+\d+\s+times[\s\S]{0,300}?Last error:\s*(?:429|5\d{2})\b/i;
+  /CAPIError:\s*(?:429\s+)?(?:429\s+quota exceeded|Too Many Requests)|Failed to get response from the AI model;\s*retried\s+\d+\s+times[^\n]{0,300}?Last error:\s*(?:429|5\d{2})\b/i;
 
 /**
  * Build a case-insensitive merged RegExp from literal/regex patterns.