Add test for URL encoded characters

Tracing URL templates should be able to include % characters. This test
is intended to show that the current implementation needs rework in
order to handle this requirement.

spec/lib/gitlab/tracing_spec.rb

@@ -44,12 +44,13 @@ describe Gitlab::Tracing do
   describe '.tracing_url' do
     where(:tracing_url_enabled?, :tracing_url_template, :correlation_id, :process_name, :tracing_url) do
-      false | "https://localhost"                                  | "123" | "web" | nil
-      true  | "https://localhost"                                  | "123" | "web" | "https://localhost"
-      true  | "https://localhost?service=%{service}"               | "123" | "web" | "https://localhost?service=web"
-      true  | "https://localhost?c=%{correlation_id}"              | "123" | "web" | "https://localhost?c=123"
-      true  | "https://localhost?c=%{correlation_id}&s=%{service}" | "123" | "web" | "https://localhost?c=123&s=web"
-      true  | "https://localhost?c=%{correlation_id}"              | nil   | "web" | "https://localhost?c="
+      false | "https://localhost"                                        | "123" | "web" | nil
+      true  | "https://localhost"                                        | "123" | "web" | "https://localhost"
+      true  | "https://localhost?service=%{service}"                     | "123" | "web" | "https://localhost?service=web"
+      true  | "https://localhost?c=%{correlation_id}"                    | "123" | "web" | "https://localhost?c=123"
+      true  | "https://localhost?c=%{correlation_id}&s=%{service}"       | "123" | "web" | "https://localhost?c=123&s=web"
+      true  | "https://localhost?c=%{correlation_id}"                    | nil   | "web" | "https://localhost?c="
+      true  | "https://localhost?c=%{correlation_id}&s=%22%{service}%22" | "123" | "web" | "https://localhost?c=123&s=%22web%22"
     end
     with_them do