[Fixed JENKINS-46054] submodule repo URL with '.url' substring failed

Modify the submodule config parsing regular expression to correctly
extract the submodule name from the config output.

Splits cli submodule URL regexp use into two cases.

git config --get-regex applies the regex to match keys, and returns all
matches (including substring matches).

Thus, a config call:

  git config -f .gitmodules --get-regexp "^submodule\.([^ ]+)\.url"

will report two lines of output if the submodule URL includes ".url":

  submodule.modules/JENKINS-46504.url.path modules/JENKINS-46504.url
  submodule.modules/JENKINS-46504.url.url https://github.com/MarkEWaite/JENKINS-46054.url

The code originally used the same pattern for get-regexp and for output parsing.
By using the same pattern in both places, it incorrectly took the first line
of output as the URL of a submodule (when it is instead the path of a submodule).

Fixes tests added in previous commits.

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

@@ -141,8 +141,24 @@ public class CliGitAPIImpl extends LegacyCompatibleGitAPIImpl {
     private StandardCredentials defaultCredentials;
     private StandardCredentials lfsCredentials;
 
+    /* git config --get-regex applies the regex to match keys, and returns all matches (including substring matches).
+     * Thus, a config call:
+     *   git config -f .gitmodules --get-regexp "^submodule\.([^ ]+)\.url"
+     * will report two lines of output if the submodule URL includes ".url":
+     *   submodule.modules/JENKINS-46504.url.path modules/JENKINS-46504.url
+     *   submodule.modules/JENKINS-46504.url.url https://github.com/MarkEWaite/JENKINS-46054.url
+     * The code originally used the same pattern for get-regexp and for output parsing.
+     * By using the same pattern in both places, it incorrectly took the first line
+     * of output as the URL of a submodule (when it is instead the path of a submodule).
+    */
+    private final static String SUBMODULE_REMOTE_PATTERN_CONFIG_KEY = "^submodule\\.([^ ]+)\\.url";
+
+    /* See comments for SUBMODULE_REMOTE_PATTERN_CONFIG_KEY to explain why this
+     * regular expression string adds the trailing space character as part of its match.
+     * Without the trailing whitespace character in the pattern, too many matches are found.
+     */
     /* Package protected for testing */
-    final static String SUBMODULE_REMOTE_PATTERN_STRING = "^submodule\\.(.*)\\.url";
+    final static String SUBMODULE_REMOTE_PATTERN_STRING = SUBMODULE_REMOTE_PATTERN_CONFIG_KEY + "\\b\\s";
 
     private void warnIfWindowsTemporaryDirNameHasSpaces() {
         if (!isWindows()) {
@@ -1092,7 +1108,7 @@ else if (!referencePath.isDirectory())
                 try {
                     // We might fail if we have no modules, so catch this
                     // exception and just return.
-                    cfgOutput = launchCommand("config", "-f", ".gitmodules", "--get-regexp", SUBMODULE_REMOTE_PATTERN_STRING);
+                    cfgOutput = launchCommand("config", "-f", ".gitmodules", "--get-regexp", SUBMODULE_REMOTE_PATTERN_CONFIG_KEY);
                 } catch (GitException e) {
                     listener.error("No submodules found.");
                     return;