Relax remote check for bwc project checkouts (#28666)

The remote check previously validated both the remote name and the
repository as well, meaning that if someone passed in a repository that
was not a github URL, it would fail. This meant that it was not possible
to fully test bwc out with multiple branches without first pushing to a
remote. Removing the full check allows a user to pass in the origin
remote as its remote, which is already added as a file based remote to
each bwc snapshot build. This will allow changes to be made locally
across all bwc branches, tested, and then pushed simultaneously.

distribution/bwc/build.gradle

@@ -68,7 +68,7 @@ subprojects {
     doLast {
       project.ext.remoteExists = false
       output.toString('UTF-8').eachLine {
-        if (it.contains("${remote}\thttps://github.com/${remote}/elasticsearch.git")) {
+        if (it.contains("${remote}\t")) {
           project.ext.remoteExists = true
         }
       }