Add no-misused/floating-promises lint rule

ts/test-mock/benchmarks/convo_open_bench.ts

@@ -11,7 +11,7 @@ import { Bootstrap, debug, stats, RUN_COUNT, DISCARD_COUNT } from './fixtures';
 const CONVERSATION_SIZE = 1000; // messages
 const DELAY = 50; // milliseconds
 
-(async () => {
+void (async () => {
   const bootstrap = new Bootstrap({
     benchmark: true,
   });

ts/test-mock/benchmarks/group_send_bench.ts

@@ -23,7 +23,7 @@ import {
 const CONVERSATION_SIZE = 500; // messages
 const LAST_MESSAGE = 'start sending messages now';
 
-(async () => {
+void (async () => {
   const bootstrap = new Bootstrap({
     benchmark: true,
   });

ts/test-mock/benchmarks/send_bench.ts

@@ -13,7 +13,7 @@ const CONVERSATION_SIZE = 500; // messages
 
 const LAST_MESSAGE = 'start sending messages now';
 
-(async () => {
+void (async () => {
   const bootstrap = new Bootstrap({
     benchmark: true,
   });

ts/test-mock/benchmarks/startup_bench.ts

@@ -10,7 +10,7 @@ const MESSAGE_BATCH_SIZE = 1000; // messages
 
 const ENABLE_RECEIPTS = Boolean(process.env.ENABLE_RECEIPTS);
 
-(async () => {
+void (async () => {
   const bootstrap = new Bootstrap({
     benchmark: true,
   });

ts/test-mock/benchmarks/storage_sync_bench.ts

@@ -9,7 +9,7 @@ import { Bootstrap } from './fixtures';
 
 const CONTACT_COUNT = 1000;
 
-(async () => {
+void (async () => {
   const contactNames = new Array<string>();
   for (let i = 0; i < CONTACT_COUNT; i += 1) {
     contactNames.push(`Contact ${i}`);