Fix firefox ability to load file, add firefox tests back (#1380)

## Launch Checklist

This PR fixes the problem with firefox not able to load a file when
clicking the open file button.
It does so by removing a very old dependency: `react-file-reader-input`
It uses the "regular" `<label><a/><input type="file" /><label>`
approach.
It adds tests for both firefox and chrome although I'm not sure the
firefox tests will stay...

 - [x] Briefly describe the changes in this PR.
 - [x] Write tests for all new functionality.
 - [x] Add an entry to `CHANGELOG.md` under the `## main` section.

cypress/e2e/maputnik-driver.ts

@@ -109,9 +109,9 @@ export class MaputnikDriver {
       this.helper.when.waitForResponse("example-style.json");
     },
     chooseExampleFile: () => {
-      this.helper.get
-        .bySelector("type", "file")
-        .selectFile("cypress/fixtures/example-style.json", { force: true });
+      this.helper.given.fixture("example-style.json", "example-style.json");
+      this.helper.when.openFileByFixture("example-style.json", "modal:open.file.button", "modal:open.file.input");
+      this.helper.when.wait(200);
     },
     setStyle: (
       styleProperties: "geojson" | "raster" | "both" | "layer" | "rectangles" | "",