Enforce strategy url requirement in latest_version

Library/Homebrew/livecheck/livecheck.rb

@@ -498,6 +498,11 @@ module Homebrew
           next
         end
 
+        if livecheck_strategy.present? && livecheck_url.blank?
+          odebug "#{strategy_name} strategy requires a url"
+          next
+        end
+
         if livecheck_strategy.present? && strategies.exclude?(strategy)
           odebug "#{strategy_name} strategy does not apply to this URL"
           next

Library/Homebrew/livecheck/strategy.rb

@@ -63,9 +63,6 @@ module Homebrew
             # Only treat the `PageMatch` strategy as usable if a regex is
             # present in the `livecheck` block
             next unless regex_provided || block_provided
-          elsif strategy == Sparkle
-            # Skip the `Sparkle` strategy if the URL is not specified explicitly.
-            next unless url_provided
           elsif strategy.const_defined?(:PRIORITY) &&
                 !strategy::PRIORITY.positive? &&
                 from_symbol(livecheck_strategy) != strategy