recentBlockhash gets overwritten

[bucurdavid]

Currently, the AnchorProvider offers the following methods for sending transactions:

1. sendAndConfirm
2. sendAll

However, issues arise when using durable nonces because the recentBlockhash field gets overwritten. It would be beneficial to add a check to determine if the field is already set or to make the sendAndConfirmRawTransaction method public to provide more flexibility.

Reference:

anchor/ts/packages/anchor/src/provider.ts

Lines 153 to 155 in 8ec7ec8

	tx.recentBlockhash = (
	await this.connection.getLatestBlockhash(opts.preflightCommitment)
	).blockhash;