revert(install-e2e): drop the 12-minute no-progress tripwire

The pre-#97052 prompt wedge fires AFTER the updater has already moved
the checkout (stash cleanup, reset, bootstrap refresh all precede the
upstream-remote prompt), so checkout movement cannot distinguish a
wedged updater from a working one. Two CI rides confirmed the check
never fires. The 35-minute wait bound already caps these legs.

tests/install/windows-e2e.ps1

@@ -758,31 +758,12 @@ function Invoke-GuiUpdateDesktopRoute([string]$TargetSha) {
         Write-Host "  waiting for the detached updater to finish (up to 35 min) ..."
         $updateLog = Join-Path $HermesHome "logs\update.log"
         $updateLogPos = 0
-        $startSha = ""
-        try { $startSha = Get-InstalledHead } catch {}
         $deadline = (Get-Date).AddMinutes(35)
-        # A working updater moves the checkout off the starting sha within its
-        # first minutes (git fetch/reset precedes the long venv + rebuild
-        # tail). No movement by this mark means the updater is wedged before
-        # its git step; waiting out the full bound adds nothing. Unreadable
-        # counts as unmoved (the wedge holds the venv shim lock, so reads can
-        # throw), but only two consecutive no-progress polls trip it: one bad
-        # read must not fail a healthy leg.
-        $progressDeadline = (Get-Date).AddMinutes(12)
-        $noProgressPolls = 0
         while ((Get-Date) -lt $deadline) {
             if (Test-Path -LiteralPath $resultPath) { break }
             $head = ""
             try { $head = Get-InstalledHead } catch {}
             if ($head -eq $TargetSha -and -not (Test-Path -LiteralPath $markerPath)) { break }
-            if ((Get-Date) -gt $progressDeadline -and ($head -eq $startSha -or $head -eq "")) {
-                $noProgressPolls++
-                if ($noProgressPolls -ge 2) {
-                    Assert-True $false "updater made progress off $startSha within 12 minutes (checkout unmoved or unreadable; wedged before its git step... on pre-#97052 releases this is the fork-upstream prompt hang)"
-                }
-            } else {
-                $noProgressPolls = 0
-            }
             # Tail any new update.log lines so the desktop-rebuild phase is
             # visible in the CI step output.
             if (Test-Path -LiteralPath $updateLog) {