Fix sidebar_details_block.vue and simplify build_metadata_entity.rb

app/assets/javascripts/jobs/components/sidebar_details_block.vue

@@ -45,7 +45,7 @@
         return `#${this.job.runner.id}`;
       },
       hasTimeout() {
-        return this.job.metadata != null && this.job.metadata.timeout_human_readable !== '';
+        return this.job.metadata != null && this.job.metadata.timeout_human_readable !== null;
       },
       timeout() {
         if (this.job.metadata == null) {

app/serializers/build_metadata_entity.rb

 class BuildMetadataEntity < Grape::Entity
-  expose :timeout_human_readable do |metadata|
-    metadata.timeout_human_readable unless metadata.timeout.nil?
-  end
-
+  expose :timeout_human_readable
   expose :timeout_source do |metadata|
     metadata.present.timeout_source
   end