fix: reviewer fetch and XMLHttpRequest issues

[BrayanDSO]

Purpose / Description

#16140 was an experiment to return to the 2.16.5 way of loading media, which worked by using the collection.media directory as base url. The pros were that files load faster and the URL is constant, so localStorage works. The cons were that it needs to accept CORS requests and doesn't work with JS fetch and XMLHttpRequest

For now my goal is just to restore compatibility with all decks. The new performance is still quite good, just ain't the best one anymore. Some ways to improve performance can be investigated later, if necessary, but now compatibility is the priority.

Fixes

• Fixes [BUG]: Visual performance regression and screen flickering on v2.18.0+ #16456
• Fixes [BUG]: XMLHttpRequest bug is still happening #16426

Approach

Revert #16140

Doesn't need a backend upgrade

How Has This Been Tested?

• Seek works on videos
• JS's fetch works
• The JS api still works

loading.webm

Checklist

Please, go through these checks before submitting the PR.

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings)
• UI Changes: You have tested your change using the Google Accessibility Scanner

[mikehardy]

Hey @BrayanDSO - do you think this is worth picking on to release-2.18?
Seems like it's worth it, to me

[david-allison]

When we next move on this change, we need better regression test coverage

A @NeedsTest somewhere relevant would be useful, just to collect the failure cases

[mikehardy]

I'm doing picks now and this fixes regressions, I'm going to be assertive, I'm putting it on the release-2.18 pile

[mikehardy]

Hmmm 🤔 I'm getting a persistent error in local testing on the release-2.18 branch and on main (./gradlew jacocoAndroidTestReport) on the JS scheduling test:

> Task :AnkiDroid:connectedPlayDebugAndroidTest

com.ichi2.anki.ReviewerTest > testCustomSchedulerWithCustomData[TestingAVD(AVD) - 14] FAILED 
        java.lang.AssertionError:
        Expected: <3000>

That seems suspiciously like the sort of thing that may break with changes in this area. It appears to work in CI though

Local environment is macOS 14.5 (current) with this debug info from emulator:

AnkiDroid Version = 2.19alpha0-debug (e605223cf0f22cf9eb0ee48b6d4e68f47205cc41)

Backend Version = 0.1.38-anki24.04.1 (24.04 429bc9e14cefb597646a0e1beac6ef140f226b6f)

Android Version = 14 (SDK 34)

ProductFlavor = play

Manufacturer = Google

Model = sdk_gphone64_arm64

Hardware = ranchu

Webview User Agent = Mozilla/5.0 (Linux; Android 14; sdk_gphone64_arm64 Build/UE1A.230829.036.A2; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/113.0.5672.136 Mobile Safari/537.36

ACRA UUID = e3ff48c8-1d2f-4017-b648-30585f787ac1

FSRS Enabled = false

Crash Reports Enabled = false

I'm going to hold off on the 2.18.1 release as I'd like to get this in, and maybe it's something trivial ?
If it looks like it will take a while to investigate and fix please just say so - it's fine - and I'll do 2.18.1 without it as that still represents incremental improvement for users, and get a fix in for 2.18.2