breaking(text-input): use native bind:value, dispatch instead of forward change, input events (#1065)

Use the native `bind:value` to fix two-way reactivity. As a result, "type" is read through `$$restProps` because it cannot be dynamic when using `bind:value`.

Extend value type to include `null` for the "number" type. This is similar to how `NumberInput` works; `null` represents "no value."

tests/TextInput.test.svelte

@@ -1,8 +1,17 @@
 <script lang="ts">
   import { TextInput, TextInputSkeleton } from "../types";
+
+  let value = null;
 </script>
 
-<TextInput labelText="User name" placeholder="Enter user name..." />
+<TextInput
+  type="number"
+  labelText="User name"
+  placeholder="Enter user name..."
+  bind:value
+  on:input="{(e) => console.log(e.detail)}"
+  on:change="{(e) => (value = e.detail)}"
+/>
 
 <TextInput
   labelText="User name"