As the title said I want to remove it from my tests. Any idea on how to do this?
This is a setting in the respective package.json file. And since those are read-only, the only option you have is to either uninstall them or to copy the contents of the package into the assets folder, remove the tests, and also remove the installed package (which means you will not get package update notifications).
I think you can also make your own menu items that filter out unwanted tests.
A great IDE would let you filter and run these tests from within the IDE. Hint: said IDE is not from Microsoft. 
I think I want to try the filter method first since this isn’t my personal project. But where do I put those? Do I just need to create a new c# file and put them? Sorry for the noob question.
No, it isn’t; it’s in the manifest.json file for the project (which is editable). The “testables” section determines which packages in your project should be included in the test runner window.
If I removed the com.unity.inputsystem it would raise an error because InputTestFixture not found
This is a longstanding issue I don’t believe there are any workarounds to. Essentially, it’s impossible to currently ship both test utilities and tests in a Unity package, as testables works together with UNITY_INCLUDE_TESTS, which is used for both test utilities and tests. There’s a thread discussing this somewhere, but I couldn’t find it easily.