Revert "[wlan][policy] Location sensor can't block scan results"

This reverts commit e2f75411a5716c4f0bbe42ab6c2452c19209d8a6.

Reason for revert: breaks compilation, raced with another change

Original change's description:
> [wlan][policy] Location sensor can't block scan results
>
> This relands commit d9f1226af09993c50626196abc1585c65e783359. PS #1
> is the same as that commit, but later PSs add fixes for the same
> flake described in https://fxrev.dev/781465
>
> Moves sending of scan results to the location sensor into its own
> future, such that it doesn't block sending scan results to any
> requesters and is instead serviced in parallel.
>
> Bug: 73821
> Bug: 76310
> Bug: 116134
> Test: fx test wlancfg-tests
> Multiply: wlancfg-tests
> Change-Id: Icddc612be3b835a40baff6742b15f593c1a0251e
> Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/781466
> Commit-Queue: Auto-Submit <[email protected]>
> Reviewed-by: Kevin Sakuma <[email protected]>
> Fuchsia-Auto-Submit: Marc Khouri <[email protected]>

Bug: 73821
Bug: 76310
Bug: 116134
Change-Id: Id557c222f8ca731fec9af7e67be5df117d0c77e6
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/781246
Reviewed-by: RubberStamper 🤖 <[email protected]>
Commit-Queue: Marc Khouri <[email protected]>