Provide a Java library with required Xiaomi telephony methods

To make this jar available to all system APKs, load it as bootjar:

```
PRODUCT_PACKAGES += \
    xiaomi-telephony-stub

PRODUCT_BOOT_JARS += \
    xiaomi-telephony-stub
```

Change-Id: I69006732e6f915dc2a5cd1a3262b7ccf37372986

telephony/Android.bp

@@ -0,0 +1,15 @@
+//
+// Copyright (C) 2024 The LineageOS Project
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+java_library {
+    name: "xiaomi-telephony-stub",
+    provides_uses_lib: "xiaomi-telephony-stub",
+    installable: true,
+    sdk_version: "system_current",
+    srcs: [
+        "src/**/*.java",
+    ],
+}

telephony/src/android/telephony/TelephonyBaseUtilsStub.java

@@ -0,0 +1,12 @@
+/*
+ * SPDX-FileCopyrightText: 2024 The LineageOS Project
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package android.telephony;
+
+public class TelephonyBaseUtilsStub {
+    public static boolean isMiuiRom() {
+        return false;
+    }
+}