fix: client-side age calculation, more glanular check for isMounted

Allows to render as much as possible on the server side.
While keeping the calculation of the age on the client side to avoid hydratation mismatch.

components/Profile/ProfileList/index.tsx

@@ -30,14 +30,17 @@ export const ProfileList = (props: ProfileListProps): JSX.Element => {
         title={i18n.translate("home.about.pronouns")}
         value={i18n.translate("home.about.pronouns-value")}
       />
-      {isMounted ? (
-        <ProfileItem
-          title={i18n.translate("home.about.birth-date")}
-          value={`${BIRTH_DATE_STRING} (${age} ${i18n.translate(
-            "home.about.years-old",
-          )})`}
-        />
-      ) : null}
+      <ProfileItem
+        title={i18n.translate("home.about.birth-date")}
+        value={
+          isMounted
+            ? `${BIRTH_DATE_STRING} (${age} ${i18n.translate(
+                "home.about.years-old",
+              )})`
+            : BIRTH_DATE_STRING
+        }
+      />
+
       <ProfileItem
         title={i18n.translate("home.about.nationality")}
         value="Alsace, France"