fix(empty-state): max-width and copy (#19670)

Co-authored-by: Dora Chan <dora.lchan@gmail.com>

src/sentry/static/sentry/app/components/onboardingPanel.tsx

@@ -31,7 +31,7 @@ const Container = styled('div')`
     justify-content: center;
     flex-wrap: wrap;
     min-height: 300px;
-    max-width: 1200px;
+    max-width: 1000px;
     margin: 0 auto;
   }
 

src/sentry/static/sentry/app/views/performance/onboarding.tsx

@@ -14,7 +14,7 @@ function Onboarding() {
       <h3>{t('Pinpoint problems')}</h3>
       <p>
         {t(
-          "You've got this souped up plan. Now what? Get your software set up. We've got transactions to track down."
+          'Something seem slow? Track down transactions to connect the dots between 10-second page loads and poor-performing API calls or slow database queries.'
         )}
       </p>
       <ButtonList gap={1}>