Revert "[JENKINS-72450] Support alternate ssh implementations on Windows" (#1717)

Windows OpenSSH hangs during `git fetch` when used from a Jenkins agent
started using the "SSH launcher" to connect to the Windows OpenSSH server
on Windows 10 and Windows 11.

Notes on the testing are in issue:

* #1715

Reopens issue:

* #1668

Reverts pull request:

* #1706

Testing done:

* Confirmed that the hang during git fetch is resolved
* Confirmed that automated tests pass

This reverts commit cd34771.

Author: MarkEWaite

src/main/java/org/jenkinsci/plugins/gitclient/CliGitAPIImpl.java

@@ -2626,15 +2626,6 @@ public File getSSHExecutable() {
             return sshexe;
         }
 
-        // Check for ssh.exe on the system PATH (supports Microsoft OpenSSH and other alternate implementations)
-        String sshPath = getPathToExe("ssh");
-        if (sshPath != null) {
-            sshexe = new File(sshPath);
-            if (sshexe.exists()) {
-                return sshexe;
-            }
-        }
-
         // Check Program Files
         sshexe = getFileFromEnv("ProgramFiles", "\\Git\\bin\\ssh.exe");
         if (sshexe != null && sshexe.exists()) {