Upload JS bundles to Sentry and set correct URL prefix

Fix several issues with the Sentry file uploads which prevented Sentry
from using the uploaded files.

 - Upload the JS bundles to Sentry as well as the sourcemaps. Sentry
   reads the `sourceMappingURL` comment from the JS

 - Set the correct URL prefix for the files, so that Sentry knows that
   eg. "sidebar.bundle.js" is served at https://cdn.hypothes.is/hypothesis/$VERSION/build/scripts/sidebar.bundle.js

   For Sentry to use a file uploaded in a release, the artifact name
   (URL prefix + name) must match the URL from which it is served (and
   referenced in crash reports). The origin of the URL can optionally be
   shortened to `~`, but we haven't done that here.

 - Finalize the release after uploading files

Jenkinsfile

@@ -28,6 +28,9 @@ node {
     // S3 bucket where the embedded client is served from.
     s3Bucket = "cdn.hypothes.is"
 
+    // URL where the embedded client will be served from.
+    cdnURL = "https://${s3Bucket}/hypothesis"
+
     // Pre-release suffix added to new package version number when deploying,
     // eg. "testing".
     //
@@ -125,11 +128,10 @@ node {
                     export SIDEBAR_APP_URL=https://qa.hypothes.is/app.html
                     export NOTEBOOK_APP_URL=https://qa.hypothes.is/notebook
                     yarn version --no-git-tag-version --new-version ${qaVersion}
-
-                    yarn run sentry-cli releases --org hypothesis --project client new ${qaVersion}
-                    yarn run sentry-cli releases --org hypothesis --project client files ${qaVersion} upload-sourcemaps build/scripts/*.map
                     """
 
+                    uploadFilesToSentry(cdnURL, qaVersion)
+
                     // Deploy to S3, so the package can be served by
                     // https://qa.hypothes.is/embed.js.
                     //
@@ -199,11 +201,10 @@ stage('Publish') {
                     export SIDEBAR_APP_URL=https://hypothes.is/app.html
                     export NOTEBOOK_APP_URL=https://hypothes.is/notebook
                     yarn version --no-git-tag-version --new-version ${newPkgVersion}
-
-                    yarn run sentry-cli releases --org hypothesis --project client new ${newPkgVersion}
-                    yarn run sentry-cli releases --org hypothesis --project client files ${newPkgVersion} upload-sourcemaps build/scripts/*.map
                     """
 
+                    uploadFilesToSentry(cdnURL, newPkgVersion)
+
                     // Create GitHub release with changes since previous release.
                     sh "scripts/create-github-release.js v${pkgVersion}"
 
@@ -246,3 +247,16 @@ String bumpMinorVersion(String version) {
 
     return "${parts[0]}.${newMinorVersion}.${parts[2]}"
 }
+
+// Upload the source files and sourcemaps for a new release to Sentry.
+//
+// See https://docs.sentry.io/product/cli/releases/#sentry-cli-sourcemaps.
+void uploadFilesToSentry(String cdnURL, String version) {
+  def sentryCmd = "yarn run sentry-cli releases --org hypothesis --project client"
+
+  sh """
+${sentryCmd} new ${version}
+${sentryCmd} files ${version} upload-sourcemaps --url-prefix ${cdnURL}/${version}/build/scripts/ build/scripts/
+${sentryCmd} finalize ${version}
+"""
+}