Prevent safecracking if wearing earphones

To increase realism and game consistency regarding partial deafness

Partially fixes #36013

Disallows an attempt at safecracking while player has
`effect_earphones`. Due to a loophole caused by mp3 player activation
being instantaneous, it is still possible to begin safecracking
immediately after putting on the mp3 player (but not after 1 turn has
passed with the mp3 active).

src/iexamine.cpp

@@ -106,6 +106,7 @@ static const efftype_id effect_mending( "mending" );
 static const efftype_id effect_pkill2( "pkill2" );
 static const efftype_id effect_teleglow( "teleglow" );
 static const efftype_id effect_sleep( "sleep" );
+static const efftype_id effect_earphones( "earphones" );
 
 static const trait_id trait_DEBUG_HS( "DEBUG_HS" );
 static const trait_id trait_AMORPHOUS( "AMORPHOUS" );
@@ -1220,6 +1221,10 @@ void iexamine::safe( player &p, const tripoint &examp )
         add_msg( m_info, _( "You can't crack a safe while deaf!" ) );
         return;
     }
+    if( p.has_effect( effect_earphones ) ) {
+        add_msg( m_info, _( "You can't crack a safe while wearing headphones!" ) );
+        return;
+    }
     if( query_yn( _( "Attempt to crack the safe?" ) ) ) {
         add_msg( m_info, _( "You start cracking the safe." ) );
         // 150 minutes +/- 20 minutes per mechanics point away from 3 +/- 10 minutes per