function splitQualifiedFieldApiName(fieldApiName) {
    const idx = fieldApiName.indexOf('.');
    if (idx < 1) {
        // object api name must non-empty
        throw new TypeError('Value does not include an object API name.');
    }
    return [fieldApiName.substring(0, idx), fieldApiName.substring(idx + 1)];
}
Split the object API name and field API name from a qualified field name.
Eg: Opportunity.Title returns ['Opportunity', 'Title']
Eg: Opportunity.Account.Name returns ['Opportunity', 'Account.Name']
@param fieldApiName The qualified field name.
@return The object and field API names.