[CLD-6487] Replace 'Country' with 'Country/Region' in country selectors (#25977)

* Replace 'Country' with 'Country/Region' in countr selectors

* Fix linteR

* Update snapshots

webapp/channels/src/components/payment_form/country_selector.tsx

@@ -29,11 +29,11 @@ const CountrySelector = (props: CountrySelectorProps) => {
             }))}
             legend={formatMessage({
                 id: 'payment_form.country',
-                defaultMessage: 'Country',
+                defaultMessage: 'Country/Region',
             })}
             placeholder={formatMessage({
                 id: 'payment_form.country',
-                defaultMessage: 'Country',
+                defaultMessage: 'Country/Region',
             })}
             name={'country_dropdown'}
         />