feat: Allow display username with uppercase characters (#43667)

* feat: Allow display username with uppercase characters

* fix: ensure user can change username to uppercased version

* fix: ensure that same username in a different case does not require validation

utils/validate.js

@@ -8,20 +8,16 @@ const usernameIsHttpStatusCode = {
   valid: false,
   error: 'is a reserved error code'
 };
-const usernameUpperCase = { valid: false, error: 'must be lowercase' };
 
 const isNumeric = num => !isNaN(num);
 const validCharsRE = /^[a-zA-Z0-9\-_+]*$/;
 const isHttpStatusCode = str =>
   isNumeric(str) && parseInt(str, 10) >= 100 && parseInt(str, 10) <= 599;
-const isUsernameLowercase = str => {
-  return str === str.toLowerCase();
-};
+
 const isValidUsername = str => {
   if (!validCharsRE.test(str)) return invalidCharError;
   if (str.length < 3) return usernameTooShort;
   if (isHttpStatusCode(str)) return usernameIsHttpStatusCode;
-  if (!isUsernameLowercase(str)) return usernameUpperCase;
   return validationSuccess;
 };
 
@@ -29,10 +25,8 @@ module.exports = {
   isNumeric,
   isHttpStatusCode,
   isValidUsername,
-  isUsernameLowercase,
   validationSuccess,
   usernameTooShort,
   usernameIsHttpStatusCode,
-  invalidCharError,
-  usernameUpperCase
+  invalidCharError
 };