feat(SubmitBar): enable safe-area-inset-bottom by default (#5956)

src/submit-bar/test/__snapshots__/index.spec.js.snap

@@ -8,6 +8,12 @@ exports[`decimal-length prop 1`] = `
 </div>
 `;
 
+exports[`disable safe-area-inset-bottom prop 1`] = `
+<div class="van-submit-bar van-submit-bar--unfit">
+  <div class="van-submit-bar__bar"><button class="van-button van-button--danger van-button--normal van-button--round van-submit-bar__button van-submit-bar__button--danger"></button></div>
+</div>
+`;
+
 exports[`disable submit 1`] = `
 <div class="van-submit-bar">
   <div class="van-submit-bar__bar">

src/submit-bar/test/index.spec.js

@@ -97,3 +97,14 @@ test('text-align prop', () => {
   });
   expect(wrapper).toMatchSnapshot();
 });
+
+test('disable safe-area-inset-bottom prop', () => {
+  const wrapper = mount(SubmitBar, {
+    context: {
+      props: {
+        safeAreaInsetBottom: false,
+      },
+    },
+  });
+  expect(wrapper).toMatchSnapshot();
+});