Adjust link checking for copilot instructions (#6824)

Disable link checking guidelines for copilot instruction files.

Co-authored-by: Wes Haggard <weshaggard@users.noreply.github.com>

eng/common/scripts/Verify-Links.ps1

@@ -530,6 +530,8 @@ foreach ($url in $urls) {
 
 LogGroupStart "Link checking details"
 
+$originalcheckLinkGuidance = $checkLinkGuidance
+
 while ($pageUrisToCheck.Count -ne 0)
 {
   $pageUri = $pageUrisToCheck.Dequeue();
@@ -538,6 +540,11 @@ while ($pageUrisToCheck.Count -ne 0)
     if ($checkedPages.ContainsKey($pageUri)) { continue }
     $checkedPages[$pageUri] = $true;
 
+    # copilot instructions require the use of relative links which is against our general guidance
+    # but we mainly care about those guidelines for docs publishing and not copilot instructions
+    # so we can disable the guidelines while validating copilot instruction files.
+    if ($pageUri -match "instructions.md$") { $checkLinkGuidance = $false }
+
     [string[]] $linkUris = GetLinks $pageUri
     Write-Host "Checking $($linkUris.Count) links found on page $pageUri";
     $badLinksPerPage = @();
@@ -561,6 +568,8 @@ while ($pageUrisToCheck.Count -ne 0)
   } catch {
     Write-Host "Exception encountered while processing pageUri $pageUri : $($_.Exception)"
     throw
+  } finally {
+    $checkLinkGuidance = $originalcheckLinkGuidance
   }
 }