chore(browser): upgrade fake-indexeddb to v6

[AbhiPrasad]

changelog: https://github.com/dumbmatter/fakeIndexedDB/blob/master/CHANGELOG.md

removes a structured clone polyfill, which is fine because we are node 18+ in the SDK. This helps reduce dep count in yarn.lock.

[github-actions]

node-overhead report 🧳

Note: This is a synthetic benchmark with a minimal express app and does not necessarily reflect the real-world performance impact in an application.

Scenario	Requests/s	% of Baseline	Prev. Requests/s	Change %
GET Baseline	8,775	-	9,643	-9%
GET With Sentry	1,377	16%	1,422	-3%
GET With Sentry (error only)	6,079	69%	6,216	-2%
POST Baseline	1,191	-	1,219	-2%
POST With Sentry	528	44%	561	-6%
POST With Sentry (error only)	1,061	89%	1,071	-1%
MYSQL Baseline	3,285	-	3,392	-3%
MYSQL With Sentry	444	14%	477	-7%
MYSQL With Sentry (error only)	2,676	81%	2,748	-3%

View base workflow run

[andreiborza]

LGTM, but I haven't checked changes between v4 and v6. Is there anything in there that could break us?

[AbhiPrasad]

Nothing from what I saw, but we can revert if we see something suspicious.