do not make a url if no deatils_path is present - use '.tag' for ref in commit component

app/assets/javascripts/vue_pipelines_index/pipelines.js.es6

@@ -88,7 +88,7 @@
                   <commit
                     :commit-icon-svg='svgs.commitIconSvg'
                     :author='author(pipeline)'
-                    :tag="pipeline.ref['tag?']"
+                    :tag="pipeline.ref.tag"
                     :title='commitTitle(pipeline)'
                     :commit-ref='ref(pipeline)'
                     :short-sha='commitSha(pipeline)'

app/assets/javascripts/vue_pipelines_index/status.js.es6

@@ -18,7 +18,7 @@
       },
       detailsPath() {
         const { status } = this.pipeline.details;
-        return status.details_path ? status.details_path : '#';
+        return status.details_path ? status.details_path : false;
       },
     },
     template: `