workflow/show_mnemonic: shorter title
Fits better between the buttons on the top.
#define NUM_RANDOM_WORDS 5
static const char* _back_label = "Back to seed phrase";
-static const char* _cancel_confirm_title = "Export Mnemonic";
+static const char* _cancel_confirm_title = "Mnemonic";
static void _split_and_save_wordlist(
char* mnemonic,
