Correct typos in Sessions info banner for Free plan users

[use-tusk]

Corrected typos and grammatical errors in the Sessions info banner for Free plan users. The main changes include:

1. Changing 'Sessions are' to 'Sessions is'.
2. Changing 'using them' to 'using it'.
3. Correcting 'September 27st' to 'September 27th'.

These changes are localized to a single file and do not require any functional modifications.

---

Browser testing result ✅

Success image

Step: [Verify] The text in the blue info banner at the top of the 'Sessions' page has been corrected to: 'Sessions is a Pro feature. In order to keep using it, you need to upgrade your plan before September 27th, 2024. Upgrade to Pro.'

The assertion is true. The text in the blue info banner at the top of the 'Sessions' page reads: 'Sessions is a Pro feature. In order to keep using it, you need to upgrade your plan before September 27th, 2024. Upgrade to Pro.' This matches the assertion exactly.

---

Tips:

• Make sure to test changes before merging.
• Submit a "Request Changes" review and I'll address it.
• Close this PR with a comment if it's obviously incorrect. This will improve my future PRs.
• Go to the Tusk activity logs to see more details.

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated (UTC)
helicone	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Sep 27, 2024 2:13am
helicone-bifrost	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Sep 27, 2024 2:13am
helicone-eu	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Sep 27, 2024 2:13am