fix: dreprecated from (self::MASTER_REQUEST) to (self::MAIN_REQUEST)

[Oluwatos94]

Q	A
Bug fix? (use the a.b branch)	[ ]
New feature/enhancement? (use the a.x branch)	[ ]
Deprecations?	[ ]
BC breaks? (use the c.x branch)	[ ]
Automated tests included?	[ ]
Related user documentation PR URL	mautic/mautic-documentation#...
Related developer documentation PR URL	mautic/developer-documentation#...
Issue(s) addressed	Fixes #...

Description:

Steps to test this PR:

1. Open this PR on Gitpod or pull down for testing locally (see docs on testing PRs here)
2. Navigate to the app/middlewares/Dev/IpRestrictMiddleware.php directory.
3. press ctrl-f in your code editor environment (Vs code) to find self::MASTER_REQUEST which is the deprecated constant.

Steps taken to resolve this problem on all located files:

1. search for the constant self::MASTER_REQUEST
2. replaced with self::MAIN_REQUEST

[Oluwatos94]

@RCheesley, Please you can now review this. I have resolved in all the locations as requested.

[Oluwatos94]

Hello, @RCheesley! you could try to test the code now. I have made some adjustment by changing deprecated constants HttpKernelInterface::MASTER_REQUEST to HttpKerrnelInterface::MAIN_REQUEST.