mosquitto: fix bug with firefox wss http/2

[rskew]

Firefox has a bug preventing websockets being created with a server that uses http/2. Building libwebsockets without http/2 support fixes this issue for mosquitto.
See eclipse-mosquitto/mosquitto#1211 (comment)

Description of changes

Override libwebsockets to be built without HTTP/2 support for mosquitto

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.11 Release Notes (or backporting 23.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

[kirillrdy]

Result of nixpkgs-review pr 244604 run on aarch64-linux 1

4 packages built:

• collectd
• domoticz
• mosquitto
• owntracks-recorder