[Trade Page] Improve token not found

[tiagofilipenunes]

• User goes to trade page with deeplink with a token that doesn’t exist anymore
• User had a strategy pair saved with a token not in the tokenlist and all strategies for it were removed (more noticeable on new deployments)
• User imports token then refreshes page

Example flow:

1. Go to trade page
2. Select a token and import a new one (for example, 0x8C67250386fff55D1D62F0f5ee89fE17Cf0E91Bf on Sei)
3. Page works fine
4. Refresh, “Token not found”

Expected: Provide either a way to change tokens or allow the page to load with an unknown pair