use map_while to count for always err case.

Reasons:
- Filter_map will run forever if iterator only returns Err with lines.
  This is a possibility for "lines" iterators.
- Map_while will break the mapping the moment the iterator returns error.

Signed-off-by: Perma Alesheikh <me@prma.dev>

src/email/message/command/save.rs

@@ -88,7 +88,7 @@ impl MessageSaveCommand {
             io::stdin()
                 .lock()
                 .lines()
-                .filter_map(Result::ok)
+                .map_while(Result::ok)
                 .collect::<Vec<String>>()
                 .join("\r\n")
         };

src/email/message/command/send.rs

@@ -110,7 +110,7 @@ impl MessageSendCommand {
             io::stdin()
                 .lock()
                 .lines()
-                .filter_map(Result::ok)
+                .map_while(Result::ok)
                 .collect::<Vec<_>>()
                 .join("\r\n")
         };

src/email/message/template/command/save.rs

@@ -92,7 +92,7 @@ impl TemplateSaveCommand {
             io::stdin()
                 .lock()
                 .lines()
-                .filter_map(Result::ok)
+                .map_while(Result::ok)
                 .collect::<Vec<String>>()
                 .join("\n")
         };

src/email/message/template/command/send.rs

@@ -113,7 +113,7 @@ impl TemplateSendCommand {
             io::stdin()
                 .lock()
                 .lines()
-                .filter_map(Result::ok)
+                .map_while(Result::ok)
                 .collect::<Vec<_>>()
                 .join("\n")
         };