Replace O(N) per-block loop in `getConfirmedEvents()` with indexed DB query

[dDevAhmed]

• Impact: Mismatch on checksummed addresses.
• Fix: toLowerCase().
• Complexity: Medium

[icedoutskay]

@icedoutskay has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

Hello, can I work on this issue?

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[Benedict07749]

@Benedict07749 has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

HELLO MAINTAINER,I work on this issue

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[Lonewolf-master]

@Lonewolf-master has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

hi maintainer, can i be issued to this task

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[Tenny150]

@Tenny150 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

i would like to work on these

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[MerlinTheWhiz]

@MerlinTheWhiz has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hi, can I work on this?

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