fix: Correctly sanitize input everywhere (#5697)

Best reviewed commit-by-commit; the commit messages explain what is
done.

src/tools.rs

@@ -22,7 +22,7 @@ pub use std::time::SystemTime;
 use anyhow::{bail, Context as _, Result};
 use base64::Engine as _;
 use chrono::{Local, NaiveDateTime, NaiveTime, TimeZone};
-use deltachat_contact_tools::{strip_rtlo_characters, EmailAddress};
+use deltachat_contact_tools::EmailAddress;
 #[cfg(test)]
 pub use deltachat_time::SystemTimeTools as SystemTime;
 use futures::{StreamExt, TryStreamExt};
@@ -511,13 +511,6 @@ pub fn parse_mailto(mailto_url: &str) -> Option<MailTo> {
     }
 }
 
-/// Sanitizes user input
-/// - strip newlines
-/// - strip malicious bidi characters
-pub(crate) fn improve_single_line_input(input: &str) -> String {
-    strip_rtlo_characters(input.replace(['\n', '\r'], " ").trim())
-}
-
 pub(crate) trait IsNoneOrEmpty<T> {
     /// Returns true if an Option does not contain a string
     /// or contains an empty string.
@@ -1025,12 +1018,6 @@ DKIM Results: Passed=true";
         assert_eq!(h, 50);
     }
 
-    #[test]
-    fn test_improve_single_line_input() {
-        assert_eq!(improve_single_line_input("Hi\naiae "), "Hi aiae");
-        assert_eq!(improve_single_line_input("\r\nahte\n\r"), "ahte");
-    }
-
     #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
     async fn test_maybe_warn_on_bad_time() {
         let t = TestContext::new().await;