{#await} blocks always cause transitionManager to be included

[Conduitry]

(Splitting this off from #1437 and closing that one, because they're kind of separate issues.)

If a component uses {#await} blocks, transitionManager will always be included, even if there are no transitions.

[Conduitry]

This looks to be a little messy to fix. The handlePromise helper function checks whether there is anything in info.blocks before calling transitionManager - but the call to transitionManager will still always be there and so is included in the bundle. We know at compile time whether info.blocks is undefined, but it seems like we'd have to have two separate shared handlePromise helpers (one with transitions and one without), but to not have too much repeated code.

[Conduitry]

My best idea so far, which I'm not thrilled with, is to make handlePromise accept a third argument that is the transitionManager, and the code generated in AwaitBlock.ts will either include or not include that third argument as appropriate. This involves a small amount of extra code when you are using outro transitions, and still carries along some unnecessary code when you are not using outro transitions, but does avoid including the whole transitionManager if you aren't using outro transitions.

[Conduitry]

This appears to have been fixed by #1569 and can be closed next release

[Rich-Harris]

fixed in 2.9.0