fix(rest): correct exponential backoff delay from seconds to milliseconds

[adickinson72]

Summary

The delay calculation 2 ** i * 0.25 produces values that are effectively sub-millisecond (0.25ms, 0.5ms, 1ms...) when passed to setTimeout, which expects milliseconds. This causes all 10 retries to complete in ~256ms instead of the intended ~256 seconds of exponential backoff.

Changes

• Changed await delay(2 ** i * 0.25) to await delay(2 ** i * 250) in packages/rest/src/Requester.ts
• Updated the retry test to use Jest fake timers since delays are now significant

New Delay Schedule

Retry	Old (ms)	New (ms)
0	0.25	250
1	0.5	500
2	1	1,000
3	2	2,000
4	4	4,000
5	8	8,000
6	16	16,000
7	32	32,000
8	64	64,000
9	128	128,000
Total	~256ms	~256s (~4.3min)

Testing

• All unit tests pass
• Linting passes
• The retry test now uses jest.useFakeTimers() and jest.runAllTimersAsync() to avoid actual waiting

Fixes #3805

[jdalrymple]

Good improvement, should have been what you have to begin with 😥