Reland "[Data Sharing] Making sure SDKDelegate is fully initialized before calling UI delegate methods."

This reverts commit ae3aa7c9dafdbdb7d9d4381753ccc4f6fd157dbd.

Reason for revert: Fixed the failing tests.

Original change's description:
> Revert "[Data Sharing] Making sure SDKDelegate is fully initialized before calling UI delegate methods."
>
> This reverts commit eef9b9b502afcab92369aa8ec495abb00ce198d4.
>
> Reason for revert: Likely candidate for causing test failures on CI bots. crbug.com/393312895
>
> Original change's description:
> > [Data Sharing] Making sure SDKDelegate is fully initialized before calling UI delegate methods.
> >
> > In this CL, making sure SDK delegate is initalised fully before UI
> > delegate methods are called. This is to make sure that any of the methods
> > of UI delegate using network loader doesn't crash because the network
> > loader which is initialised by SDK is not initialised.
> >
> > Bug: 393184221
> > Change-Id: I682538f6a83439323e681b332734e9767e39ca36
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6217143
> > Commit-Queue: Ritika Gupta <ritikagup@google.com>
> > Reviewed-by: Siddhartha S <ssid@chromium.org>
> > Auto-Submit: Ritika Gupta <ritikagup@google.com>
> > Cr-Commit-Position: refs/heads/main@{#1413275}
>
> Bug: 393312895
> Change-Id: I5c8c98c9cf8c772991cf66f8be80427d844748d0
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6216865
> Commit-Queue: Rupert Wiser <bewise@chromium.org>
> Owners-Override: Rupert Wiser <bewise@chromium.org>
> Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> Cr-Commit-Position: refs/heads/main@{#1413408}

Bug: 393312895
Change-Id: Iad20d2dc595788b9c0e7f9947addb3f164e3c9cd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6219335
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Siddhartha S <ssid@chromium.org>
Commit-Queue: Siddhartha S <ssid@chromium.org>
Auto-Submit: Ritika Gupta <ritikagup@google.com>
Commit-Queue: Ritika Gupta <ritikagup@google.com>
Cr-Commit-Position: refs/heads/main@{#1413660}