[Bug]: UI not using pre-sign when showing Uncommitted object changes

[Isan-Rivkin]

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What happened?

When using lakeFS in Minimal Permissions in S3 In Uncommitted Changes > "Show object changes" > Error: S3 Access Denied.

Users are not able to see object changes in the UI. If users configured presigned mode via disable_pre_signed_ui they are expecting the UI to use presign URLs but it does not and instead uses lakeFS getObject regular API. If using minimal IAM permissions: Users are not able to see object changes in the UI and will get an error.

Steps to Reproduce:

1. Configure lakeFS server to use presign URL in AWS disable_pre_signed_ui.
2. Do some file action (i.e delete object) and don't commit.
3. Go to UI > Uncommitted changes > "Show object changes" > Inspect network tab: the UI does not specify presign=true when calling getObject.

Expected behavior

The UI should use presign=true to fetch the object and show the changes.

Root Cause

The UI should pass presign=true when calling getObject in Diff here and here