How to configure browser used by web page Reminders?

How can I change which browser the Mac Reminders.app uses to open "this webpage" associations for a Reminder, so I can change the "Open Google Chrome Canary" notification button to an "Open Mozilla Firefox" button?

Given I've created a Reminder for a Webpage on my phone by asking Siri to "remind me about this tomorrow", when the Reminder appears on my laptop running the latest public build of OS X, then I expect the Open button to offer to open it in my default browser, or just not mention the browser and behave as open(1) does.

Instead, what I see is "Open in Google Chrome Canary":

This has me flummoxed: I open that browser like once a year, and my default browser is Mozilla Firefox. I've no clue why Reminders has latched onto it as The Chosen Browser for webpage reminders.

ETA: I have deleted Google Chrome Canary. After relaunching Reminders.app, webpage reminders show, instead of its icon, the "invalid app" default icon with slashed-circle. Clicking that button does nothing. No console logs appear. 💯

Solution 1:

My results from user edgarator’s solution: Successful for macOS Safari users

Summary

• Chrome icon changed to Safari after CleanMyMac Chrome Uninstall
• Chrome icon appears again after Chrome is reinstalled
• Removing files individually still had the Chrome icon, resulting in “no effect”
• Firefox will open Reminders URL’s if it is set as the default web browser.
• Firefox can’t share websites to Reminders.
• Firefox can’t use Siri to send websites to Reminders.

Software Versions

• macOS Sierra: 10.12.6
• Apple Reminders: 4.0 (441.11)
• CleanMyMac: 1.10.4
• Google Chrome: 61.0.3163.79 (Official Build) (64-bit)
• Safari: 10.1.2 (12603.3.8)
• Firefox: 55.0.3 (64-bit)

My Process

Safari’s has a share website to Reminders feature (Share-to-Reminders). Details can be added to a website reminder that is being sent to Reminders without leaving the browser.

Now the problem: The shared links in Reminders uses Chrome icons which open Reminders items in Chrome, instead of Safari—or a designated browser.
I used CleanMyMac to uninstall Google Chrome, it's folders, and files.

After uninstalling Chrome, it's icon was replaced by Safari’s icon, pressing on the icon opened the link in Safari. I then changed the default web browser to Firefox.

Clicking on the URL’s directly, or Control-clicking the URL’s in the Info Pane, opens the link in Firefox (default browser).

However, Firefox does not support Share-to-Reminders, so websites can’t be shared to Reminders from Firefox. This also means that Siri does not execute the Share-to-Reminders command while using Firefox.

Solution 2:

CleanMyMac 3 has a feature called "Rebuild Launch Services Database", which fixed the issue for me, resetting the browser from Chrome to Safari.