feat(billing): support initial billing limit for data warehouse

[raquelmsmith]

Problem

We are setting an initial billing limit of $500 for data warehouse users just in case they decide to sync a very large database without realizing it. This limit shows up on the billing page, so users should know why it's there, and also be alerted that it exists when they set up their first sync.

Changes

1. Tells users on billing page if it's an initial limit and why it's there

2. Alerts users about initial limit after setting up their first sync.

   • Shows persistently until cleared with the X
   • only if the current billing limit matches the initial limit
   • only if they have more than 1 source set up (no sense in telling them if they haven't set something up)

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Does this work well for both Cloud and self-hosted?

Shouldn't impact self-hosted as they can't have billing limits set

How did you test this code?

👀

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| Filename | Size | | :--- | :---: | | `frontend/dist/toolbar.js` | 1.06 MB |

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