OCPBUGS-77830: skip redirect when validating endpoint accessibility

The installer uses HTTP HEAD to validate if user-provided service
endpoint URLs are reachable. However, in some cases, the request results
in a redirect to AWS doc URL, which can causes install failure in
disconnected environment. The users should not be required to open
access to AWS docs to install.

For example:

$ curl --head https://sts.ap-southeast-1.amazonaws.com
HTTP/1.1 302 Found
Location: https://aws.amazon.com/iam

Author: tthvo

pkg/asset/installconfig/aws/validation.go

@@ -864,9 +864,18 @@ func validateEndpointAccessibility(endpointURL string) error {
 	if _, err := url.Parse(endpointURL); err != nil {
 		return fmt.Errorf("failed to parse service endpoint url: %w", err)
 	}
-	if _, err := http.Head(endpointURL); err != nil { //nolint:gosec
+
+	client := &http.Client{
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse // Don't follow redirects
+		},
+	}
+	resp, err := client.Head(endpointURL)
+	if err != nil {
 		return fmt.Errorf("failed to connect to service endpoint url: %w", err)
 	}
+	defer resp.Body.Close()
+
 	return nil
 }