enable_authenticated_media and 3 ways to save media file

### Steps to reproduce

0. Enable **enable_authenticated_media** in the synapse config (enabled by default)

1. If you right-click on the image in **Element Desktop** and select "Save image as..", the application tries to save the **jpg** file to a local disk and as a result a window appears with the error "The image failed to save".

At the same time, synapse logs contain an URL request "/_matrix/media/v3/download/otr.ru/iLMjSsUhyMEATImoCaIJTQhv?allow_redirect=true"

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2. If you right-click on the image in **Element Web** and select "Save image as..", the browser tries to save the **json** file and as a result the error "File wasn't available on site".



synapse logs contain an URL request "/_matrix/media/v3/thumbnail/otr.ru/iLMjSsUhyMEATImoCaIJTQhv?width=800&height=600&method=scale&allow_redirect=true"

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3. If you click the "**Download**" button in **Element Web/Desktop**, the file is saved without problems.


synapse logs contain an URL request "/_matrix/client/v1/media/download/otr.ru/iLMjSsUhyMEATImoCaIJTQhv?allow_redirect=true"

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Why are different URLs requested in each of these methods? Can you make all three methods work?

### Outcome

#### What did you expect?
The file is being downloaded

#### What happened instead?
Аn error has occurred

### Operating system

Windows

### Application version

Element 1.12.6

### How did you install the app?

_No response_

### Homeserver

Synapse 1.143

### Will you send logs?

No

No source files or tests are identified in the report. Reproduce the three Element Web/Desktop save paths with enable_authenticated_media enabled, compare the requested media URLs, and trace the client code that constructs them; done means right-click saving works in both clients as well as the existing Download button.

Written by the indexing model from the issue text.