fix(useIntervalFn): watch interval correctly

[meteorlxy]

Description

Currently, once the interval is changed, the intervalFn will:

• always resume when immediate = true, even if it is not active
• never resume when immediate = false, even if it is active

It seems like a bug, because we should respect the isActive instead.

Additional context

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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