feat(wallet.svelte): integrate pkpWallet into state store

- Initialize pkpWallet with null value inside the component store.
- Update store's pkpWallet upon successful wallet connection.
- Reflect pkpWallet value reactively in the UI.

BREAKING CHANGE: The pkpWallet now resides in the component's store and should be accessed as $store.pkpWallet.

src/routes/+page.svelte

@@ -4,11 +4,11 @@
 	let componentsData = {
 		layout: {
 			areas: `   
-				"header header header"
-				"main main aside"
-				"footer footer footer";
+				"header  main"
+				"aside  main"
+				"footer  footer";
 			`,
-			columns: '1fr 1fr 1fr',
+			columns: '1fr 1fr',
 			rows: 'auto 1fr auto'
 		},
 		children: [
@@ -19,15 +19,20 @@
 				services: ['setupLit']
 			},
 			{
-				id: '2',
+				id: 'messages',
 				componentName: 'Messages',
-				slot: 'main'
+				slot: 'main',
+				store: {
+					prop1: 'prop1',
+					prop2: 'prop2'
+				}
 			},
 			{
-				id: '4',
+				id: 'wallet',
 				componentName: 'Wallet',
 				slot: 'aside',
-				state: {
+				store: {
+					pkpWallet: '',
 					rpcURL: 'https://rpc.gnosischain.com/',
 					pkpPubKey:
 						'046da3ba67065fd1e2726242ca01cd4601524893f4aa4b0042578fa6cbec28fa8c9a28eb9f7893932fc09717edc9e1db57e157a21eed346247c1db5a722a01f571'