Fix extract_first_email_addr() to really return the first email

The use of find_all() in extract_email_addrs_vec() extracted occurrences
to an intermediate set and thus lost any sense of ordering.

This changes extract_email_addrs_vec() to use find_all_ordered() and
return all occurrences of email addresses found in the argument,
included duplicates, with their order of occurrence preserved.

NEWS

@@ -27,6 +27,11 @@ Changed Functionality
   - The use as enum of type ``NetControl::RuleType`` is unchanged and still
     named ``NetControl::DROP``
 
+- The extract_email_addrs_vec() BIF now returns all occurrences of emails,
+  including duplicates, with preserved order of occurrence.  This seems like
+  the original/documented intent of the function, but the previous
+  implementation did not preserve ordering or duplicates.
+
 Removed Functionality
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