Rename icons, primitives tsconfig to _tsconfig

[#21613](#21613) "hid"
TypeScript emitted type declarations for `@wordpress/element` when it
was found to conflict with 3rd party type declarations on
DefinitelyTyped.

Disabling `@wordpress/element` cascaded to require disabling type
checking for `@wordpress/icons` and `@wordpress/primitives`, two
dependent packages.

The lint-staged flow is slightly different from the full
`build:package-types` script in that it attempts to do a minimal build
in the interest of speed. This flow checks for the presence of a
`tsconfig.json` file in the root of the package with changes and runs
its package build.

While removing the affected packages from the main tsconfig.json did
remove them from the primary build, changes to primitives and icons
packages will fail because they cannot find the `@wordpress/element`
types as was intended in #21613.

By renaming the package tsconfig.json files, they are excluded from the
lint-staged typechecking as well.