Fix e2e icon colour (#30299)

* fix: remove white background on e2e verification icon and put white on the checkmark

* test(e2e): add non regression tests

* chore: remove unused CSS mask

playwright/e2e/crypto/crypto.spec.ts

@@ -168,6 +168,7 @@ test.describe("Cryptography", function () {
 
             // Take a snapshot of RoomSummaryCard with a verified E2EE icon
             await expect(page.locator(".mx_RightPanel")).toMatchScreenshot("RoomSummaryCard-with-verified-e2ee.png");
+            await expect(page.locator(".mx_MessageComposer_e2eIcon")).toMatchScreenshot("composer-e2e-icon.png");
         },
     );