The answer is a resounding no. There is no legal restriction for this, and the choice ultimately lies with the consumer as to where to get their vehicle serviced. Now mind you, there are very specific requirements from the manufacturer that must be met in order to keep your warranty valid, so the proper type of oil, filter, and service intervals must be followed. In fact, just last week “Right to Repair” legislation was tabled in Canada to help secure consumer choice.
A reputable independent shop should be able to recognize what items require returning to the dealership for warranty coverage, but for most things there is freedom of choice to care for your investment.