Fix: If two images are posted within the same second, only the first one will be saved.

[KhushamBansal]

Checklist

• Ensure your code works with manual testing.
• New or updated public/exported symbols have accurate TSDoc documentation.
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My approach to solve the issue:

Added a timestamp to the filename:
Used Date.now() to get the current time in milliseconds.
Modified the targetFileName to include the timestamp, ensuring uniqueness.
Closes element-hq/element-web#29079

[CLAassistant]

All committers have signed the CLA.

[MidhunSureshR]

Not sure what this is fixing, please provide some more context

[KhushamBansal]

Here is the issue I have work on: element-hq/element-web#29079
If two images are posted within the same second, only the first one will be saved.
My approach to solve the issue:
Added a timestamp to the filename:
Used Date.now() to get the current time in milliseconds.
Modified the targetFileName to include the timestamp, ensuring uniqueness.

[t3chguy]

The title is misleading, this change looks entirely unrelated to the export chat feature..

[dbkr]

Hello! You've updated the PR title but the description still links to the bug that this PR doesn't fix. I don't think there is a bug for the behaviour this PR is actually changing, and I'm not really sure how much of a problem it would be: most browsers will automatically append a '(1)' or similar if a file already exists by the same name. This would mean all downloaded files get a timestamp appended which doesn't seem desirable.

I think the best thing to do here might to apply a similar change to fix the original bug, which would be in the element-web repo, which I think would be https://github.com/element-hq/element-web/blob/a0044d6b5f841acd48870dcc99ff6f27f0248f61/src/utils/exportUtils/HtmlExport.tsx#L378 and corresponding places in the other exporters, ideally.