Fix fees in WASM planner

[jessepinho]

After some recent changes to the non-WASM/"regular" planner, the WASM planner was out of sync as regards fee handling. This PR gets it back in sync.

Manual testing (optional reading, but here for posterity)

This was hard to test because of some issues in Penumbra core. Steps I took to test it:

• Rebase this PR onto commit 1d368d4 per this Discord discussion about a broken state in core's main branch
• Set fees in crates/core/component/fee/src/genesis.rs:

        fn default() -> Self {
            Self {
                fee_params: FeeParameters::default(),
   -            gas_prices: GasPrices::default(),
   +            gas_prices: GasPrices {
   +                block_space_price: 1,
   +                compact_block_space_price: 2,
   +                execution_price: 3,
   +                verification_price: 4,
   +            },
            }
        }

• Compile the WASM planner (with this PR's changes included) to JS (cd crates/wasm/publish && pnpm install && pnpm run compile-wasm)
• In the web mono-repo, check out my PR: Support fees in Penumbra web web#362
• Install the newly built version of the WASM planner in the web monorepo (pnpm install ../penumbra-core/crate/wasm/publish/bundler; note that you first have to uninstall @penumbra-zone/wasm-bundler from both the root of the web monorepo and the packages/wasm directory)
• Modify packages/constants/config.ts to set the grpcEndpoint to http:/localhost:8080

[jessepinho]

Changes copied from

penumbra/crates/view/src/planner.rs

Lines 172 to 192 in 1d368d4

	pub fn add_gas_fees(&mut self) -> &mut Self {
	// Add a single Spend + Output to the minimum fee to cover paying the fee
	let minimum_fee = self
	.gas_prices
	.fee(&(self.plan.gas_cost() + gas::output_gas_cost() + gas::spend_gas_cost()));
	// Since paying the fee possibly requires adding additional Spends and Outputs
	// to the transaction, which would then change the fee calculation, we multiply
	// the fee here by a factor of 128 and then recalculate and capture the excess as
	// change outputs.
	//
	// TODO: this is gross and depending on gas costs could make the gas overpayment
	// ridiculously large (so large that the account may not have notes available to cover it)
	// or too small. We may need a cyclical calculation of fees on the transaction plan,
	// or a "simulated" transaction plan with infinite assets to calculate fees on before
	// copying the exact fees to the real transaction.
	let fee = Fee::from_staking_token_amount(minimum_fee * Amount::from(128u32));
	self.balance -= fee.0;
	self.plan.transaction_parameters.fee = fee.clone();
	self
	}

[zbuc]

LGTM!