With their leaders still recommending approval of a new contract, but its passage by no means certain, Hollywood writers took a final vote on whether to continue their 13-day-old strike against film and television producers. The official tally will be announced at a news conference today. The meeting of the West Coast branch of the Writers Guild of America was held at the Hollywood Palladium, where after a noisy four-hour session on March 11, members delayed a final vote for a week, after unexpectedly balking at approving the new contract. A total of 5,100 Los Angeles guild members were eligible to vote. Those who cast ballots at last week's meeting were allowed to reverse their vote during the latest tally if desired.