fix: make call action receiver private (#493)

The app shouldn't allow third-party apps to accept/end calls.

Author: naveensingh

app/src/main/AndroidManifest.xml

@@ -193,12 +193,7 @@
         <receiver
             android:name=".receivers.CallActionReceiver"
             android:enabled="true"
-            android:exported="true">
-            <intent-filter>
-                <action android:name="org.fossify.phone.action.ACCEPT_CALL" />
-                <action android:name="org.fossify.phone.action.DECLINE_CALL" />
-            </intent-filter>
-        </receiver>
+            android:exported="false" />
 
         <activity-alias
             android:name=".activities.SplashActivity.Red"

app/src/main/kotlin/org/fossify/phone/helpers/Constants.kt

@@ -25,7 +25,7 @@ const val ALL_TABS_MASK = TAB_CONTACTS or TAB_FAVORITES or TAB_CALL_HISTORY
 val tabsList = arrayListOf(TAB_CONTACTS, TAB_FAVORITES, TAB_CALL_HISTORY)
 
 private const val PATH = "org.fossify.phone.action."
-const val ACCEPT_CALL = PATH + "accept_call"
-const val DECLINE_CALL = PATH + "decline_call"
+const val ACCEPT_CALL = PATH + "ACCEPT_CALL"
+const val DECLINE_CALL = PATH + "DECLINE_CALL"
 
 const val DIALPAD_TONE_LENGTH_MS = 150L // The length of DTMF tones in milliseconds