fix: Allow custom RPC URL in FeeService class

[muckee]

The existing code uses the RPC_URL constant defined in the constant.ts file to instantiate a new web3 connection.

With these changes, a Connection can be optionally passed to the getOptimalComputeUnitLimitAndPrice function, which is used to override the connection defined in the constructor of the FeeService class when Connection.simulateTransaction is executed.

Additionally, inside the referral.ts file, the referral provider's connection property is passed to feeService.getOptimalComputeUnitLimitAndPrice to ensure that the fee service can make use of custom RPC URLs passed to the provider.

[vercel]

@NerdMuckee is attempting to deploy a commit to the wowcats Team on Vercel.

A member of the Team first needs to authorize it.

[muckee]

Just thought to mention...

I decided to forward the connection as a separate parameter, instead of adding it to the payload described by GetOptimalComputeUnitLimitAndPricePayload.

I assumed that your intended definition of 'payload' describes data included in the blockchain interaction, as opposed to all of the data passed as props within JS.

Let me know if you want me to edit the PR so that the connection is passed as one of the properties of GetOptimalComputeUnitLimitAndPricePayload, instead of as a separate parameter.