Chore: remove plausible scripts (#63054)

Plausible is no longer being used, so this removes it from the web app.

cmd/frontend/internal/app/ui/app.html

@@ -47,9 +47,6 @@
 	<!-- Sentry -->
 	<script src='https://js.sentry-cdn.com/ae2f74442b154faf90b5ff0f7cd1c618.min.js' crossorigin="anonymous"></script>
 	<!-- End Sentry -->
-	<!-- Plausible -->
-	<script src="https://plausible.io/js/plausible.js" defer data-domain="sourcegraph.com"></script>
-	<!-- End Plausible -->
 	{{ end }}
 	<script ignore-csp>
 		window.context = {{.Context }}

doc/_resources/assets/docsite.js

@@ -117,19 +117,6 @@ document.addEventListener('DOMContentLoaded', () => {
   }
 })
 
-// Cloud CTA clicks
-document.addEventListener('DOMContentLoaded', () => {
-  const cloudCTAs = document.querySelectorAll('.cloud-cta')
-
-  cloudCTAs.forEach(cloudCTA => {
-    cloudCTA.addEventListener('click', () => {
-      if (window && window.plausible) {
-        window.plausible('ClickedOnFreeTrialCTA')
-      }
-    })
-  })
-})
-
 // Promise to wait on for DOMContentLoaded
 const domContentLoadedPromise = new Promise(resolve => {
   if (document.readyState === 'loading') {

doc/_resources/templates/root.html

@@ -28,10 +28,6 @@
 			{{block "seo" . }}{{end}}
 			{{block "head" .}}{{end}}
 
-            <!-- Plausible -->
-            <script src="https://plausible.io/js/plausible.js" defer data-domain="docs.sourcegraph.com"></script>
-            <!-- End Plausible -->
-
             <!-- Google Tag Manager -->
             <script>
                 (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':