Add Views to BalancesResponse

[grod220]

Pairs with: penumbra-zone/penumbra#3824

Web app currently takes assetId+amount response and transforms it to AddressView+ValueView:

web/apps/webapp/src/fetchers/balances/index.ts

Lines 44 to 79 in fa68d2d

	const constructAssetBalanceWithMetadata = async ({
	balance,
	account,
	}: BalancesResponse): Promise<AssetBalance> => {
	if (!balance) throw new Error('No balance in response');
	if (!account) throw new Error('No account in response');
	const value = await getValueView(balance);
	const address = await getAddressView(account);
	const usdcValue = await calculateUsdcValue(balance);
	return { value, address, usdcValue };
	};
	const getValueView = async (balance: Value): Promise<ValueView> => {
	if (!balance.assetId) throw new Error('no asset id in balance');
	if (!balance.amount) throw new Error('no amount in balance');
	const { denomMetadata } = await viewClient.assetMetadataById({ assetId: balance.assetId });
	if (!denomMetadata) {
	return new ValueView({
	valueView: { case: 'unknownAssetId', value: balance },
	});
	} else {
	return new ValueView({
	valueView: {
	case: 'knownAssetId',
	value: {
	amount: balance.amount,
	metadata: denomMetadata,
	},
	},
	});
	}
	};

After new protos, this should move into balances view rpc method in extension.

While here, should delete calculateUsdcValue() in web app as extension now provides pricing.