Respect cache mode when loading external dependencies.

[HolonProduction]

This line is part of #86960, but this seems to have quite a way ahead of it and I need it to fix the CI for #86973.

Also this might fix
#82830

[AThousandShips]

This should also be done in the binary format if done here, the same code is used there with the reuse mode

godot/core/io/resource_format_binary.cpp

Line 686 in f8a039e

external_resources.write[i].load_token = ResourceLoader::_load_start(path, external_resources[i].type, use_sub_threads ? ResourceLoader::LOAD_THREAD_DISTRIBUTE : ResourceLoader::LOAD_THREAD_FROM_CURRENT, ResourceFormatLoader::CACHE_MODE_REUSE);

You also have:

godot/core/io/resource_format_binary.cpp

Line 433 in f8a039e

Ref<Resource> res = ResourceLoader::load(path, exttype);

Which might be good to also make use the same cache mode

[HolonProduction]

Done

[RandomShaper]

I think this change makes sense. I'd like more people looking into it, though.

One thing I'd like to point out is that, maybe, the editor is relying on the current behavior not to have to reload external resources when loading a scene:

godot/editor/editor_node.cpp

Line 3857 in fb10e67

Ref<PackedScene> sdata = ResourceLoader::load(lpath, "", ResourceFormatLoader::CACHE_MODE_REPLACE, &err);

If that were the case, we may need to add a mode, such as CACHE_MODE_REPLACE_ROOT_REUSE_OTHERS, but with a more compact name.

[RandomShaper]

There's another issue. During export, CACHE_MODE_IGNORE is used to load PackedScenes. As a result of that, with this PR applied, the path to base scenes is lost and, therefore, when the exported version of a scene is written to the export directory, an error is printed ("Resource file not found: res:// (expected type: )") and the export data is incomplete.

[RandomShaper]

One thing I'd like to point out is that, maybe, the editor is relying on the current behavior not to have to reload external resources when loading a scene:

godot/editor/editor_node.cpp

Line 3857 in fb10e67

Ref<PackedScene> sdata = ResourceLoader::load(lpath, "", ResourceFormatLoader::CACHE_MODE_REPLACE, &err);

If that were the case, we may need to add a mode, such as CACHE_MODE_REPLACE_ROOT_REUSE_OTHERS, but with a more compact name.

On an n-th thought, if replace is meant to change the way subresources are loaded, I does make sense that the mode is just propagated.

UPDATE: But propagating would mean that subresources of external resources also get the same treatment, when the external resources themselves don't. That doesn't seem correct. So, I'd be back to my original statement.

[HolonProduction]

The change seems to be far more critical than I thought it would be. Closing in favor of #88664.