Only touch the regex file if it doesn't already exist

The other permission calls will always be run so that the file is in the
expected state after install and repair.

Signed-off-by: Mcat12 <newtoncat12@yahoo.com>

automated install/basic-install.sh

@@ -1237,7 +1237,9 @@ installConfigs() {
     version_check_dnsmasq
 
     # Install an empty regex file
-    touch "${regexFile}"
+    if [[ ! -f "${regexFile}" ]]; then
+        touch "${regexFile}"
+    fi
     chown pihole:pihole "${regexFile}"
     chmod 664 "${regexFile}"