Adding apiHost from segment.io settings, or default

[MichaelGHSeg]

Note that cdnURL has to include protocol (https://), but apiHost must not)

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[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: c143e4f036dcd02799999d90bad56da9ebfb9820

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

| Name | Type | | ----------------------- | ----- | | @segment/analytics-next | Minor |

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