feat: support async api key fetching (browser SDK)

[wrn14897]

Ref: HDX-3042

[changeset-bot]

🦋 Changeset detected

Latest commit: 3303647

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

This PR includes changesets to release 1 package

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@hyperdx/browser	Patch

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[fneves]

this is not going to work because of

hyperdx-js/packages/otel-web/src/index.ts

Lines 513 to 517 in 3303647

	if (inited) {
	diag.warn('Rum already init()ed.');
	return;
	}

[fneves]

also are there any implications of initialising > 1 times?
I thought about calling Rum.deinit() before reinitializing, but not sure about the impact

[wrn14897]

my understanding is the initWithApiKey will be called once the api key is fetched. for reinit, I don't think the api is exposed on the browser sdk side. what's the use case?