fix(website/setup.mdx): add typia installation step for pnpm/yarn

This commit adds an additional step to the setup instructions in
setup.mdx. The new step instructs the user to install the 'typia'
package using either 'pnpm' or 'yarn' package managers.

website/pages/docs/setup.mdx

@@ -601,13 +601,15 @@ npx typia setup
   <Tab>
 ```bash filename="Terminal" showLineNumbers copy
 pnpm dlx jsr add -D @ryoppippi/unplugin-typia
+pnpm install typia
 pnpm typia setup --manager pnpm
 ```
   </Tab>
   <Tab>
 ```bash filename="Terminal" showLineNumbers copy
 # YARN BERRY IS NOT SUPPORTED
 yarn dlx jsr add -D @ryoppippi/unplugin-typia
+yarn add typia
 yarn typia setup --manager yarn
 ```
   </Tab>