Suisin/Update validation rules (#6145)

* update letter symbol rules

* new rulels

* Update declarative-validation-rules.js

packages/shared/src/utils/validation/declarative-validation-rules.js

@@ -14,7 +14,7 @@ export const validAddress = value => !/[`~!$%^&*_=+[}{\]\\"?><|]+/.test(value);
 export const validPostCode = value => value === '' || /^[A-Za-z0-9][A-Za-z0-9\s-]*$/.test(value);
 export const validTaxID = value => /(?!^$|\s+)[A-Za-z0-9./\s-]$/.test(value);
 export const validPhone = value => /^\+?([0-9-]+\s)*[0-9-]+$/.test(value);
-export const validLetterSymbol = value => /^([a-zA-Z'-.]+\s)*[a-zA-Z'-.]+$/.test(value);
+export const validLetterSymbol = value => /^[A-Za-z]+([a-zA-Z'-.]+\s)*[a-zA-Z'-.]+$/.test(value);
 export const validLength = (value = '', options) =>
     (options.min ? value.length >= options.min : true) && (options.max ? value.length <= options.max : true);
 export const validPassword = value => /(?=.*[a-z])(?=.*[A-Z])(?=.*\d)[a-zA-Z\d]+/.test(value);