prefs: make some preferences translatable

Change-Id: I7cf02b4fffcf12232661cdf03f02d068b37110a5
diff --git a/ring-android/app/src/main/res/values/strings_account.xml b/ring-android/app/src/main/res/values/strings_account.xml
index 0f0ca6f..5dade49 100644
--- a/ring-android/app/src/main/res/values/strings_account.xml
+++ b/ring-android/app/src/main/res/values/strings_account.xml
@@ -162,6 +162,7 @@
     <string name="account_tls_server_name_label">Server Name</string>
     <string name="account_tls_verify_server_label">Verify Server</string>
     <string name="account_tls_verify_client_label">Verify Client</string>
+    <string name="account_require_client_certificate_label">TLS Require Client Certificate</string>
     <string name="account_tls_negotiation_timeout_sec">Negotiation Timeout (sec)</string>
     <string name="account_rtp_max_port">Maximum</string>
     <string name="account_rtp_min_port">Minimum</string>