Fix race condition when adding multiple reactions to six-hour reminder message

[QuantumManiac]

Description

Fixed an issue where "react if coming or not" reaction emojis on six-hour reminder messages would not be added to the message in the right order. This was caused by the two calls to addReactionToMessage being too close to each other and therefore resulting in a race condition. Fix is to add a small manual delay in between.

Developer Testing

Testing done:

• Manually tested on the development slack workspace

Reviewer Testing

• N/A

---

This change is 

[Darth-Raazi]

Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @billyao021031, @jeffrey-huang-yz, @Panizghi, @PCModeActivate, @shirleyfyx, @slightlyskepticalpotat, and @yxyyeah)

[shirleyfyx]

Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @billyao021031, @jeffrey-huang-yz, @Panizghi, @PCModeActivate, @slightlyskepticalpotat, and @yxyyeah)