feat(storage): use mdbx_txn_reset to time out transactions

[shekhirin]

DO NOT MERGE: running on Mainnet and Holesky over the weekends

Ref #6850, attempt number two.

Fixes several things:

1. Replaced a usage of MDBX_TXN_FINISHED flag with one atomic bool

   reth/crates/storage/libmdbx-rs/src/transaction.rs

   Lines 541 to 545 in 61bbe2f

   	// Importantly, we can't rely on `MDBX_TXN_FINISHED` flag to check if the transaction is timed
   	// out using `mdbx_txn_reset`, because MDBX uses it in other cases too.
   	fn is_timed_out(&self) -> bool {
   	self.timed_out.load(std::sync::atomic::Ordering::SeqCst)
   	}

2. Try locking the TransactionPtr mutex first, log on failure, then lock again in a blocking way

   reth/crates/storage/libmdbx-rs/src/transaction.rs

   Lines 551 to 563 in 61bbe2f

   	fn lock(&self) -> MutexGuard<'_, ()> {
   	if let Some(lock) = self.lock.try_lock() {
   	lock
   	} else {
   	tracing::warn!(
   	target: "libmdbx",
   	txn = %self.txn as usize,
   	backtrace = %std::backtrace::Backtrace::force_capture(),
   	"Transaction lock is already acquired, blocking..."
   	);
   	self.lock.lock()
   	}
   	}

3. Move a bunch of txn_execute usages back to their original places 75fa00c
4. Do not ignore mdbx_result errors on Drop, unwrap() instead.

[DaniPopes]

lgtm