fix(01-quickstart): don't abort on model inspect probe under ErrorActionPreference Stop

A missing model makes 'docker model inspect' write to stderr, which
$ErrorActionPreference = 'Stop' turns into a terminating error, killing
the script before the pull step on a fresh install. Lower the preference
to Continue only around the probe and key off $LASTEXITCODE.

Author: ppiova

01-quickstart/quickstart.ps1

@@ -21,8 +21,14 @@ if ($LASTEXITCODE -ne 0) {
 docker model status
 
 Write-Host "==> 2/5 Pulling model '$Model' (skipped if already present)"
+# Probe for the model without aborting: a missing model makes `docker model inspect`
+# write to stderr, which $ErrorActionPreference = "Stop" would turn into a terminating error.
+$prevEap = $ErrorActionPreference
+$ErrorActionPreference = "Continue"
 docker model inspect $Model *> $null
-if ($LASTEXITCODE -eq 0) {
+$modelExists = $LASTEXITCODE -eq 0
+$ErrorActionPreference = $prevEap
+if ($modelExists) {
     Write-Host "    '$Model' is already available locally, skipping pull."
 } else {
     docker model pull $Model