fix(tauri-utils): preserve resource source file name when dest is empty

[Legend-Master]

Fix #15380, regression from #14662

Apparently #14662 (comment) is possible

This behavior is confusing, but we should still keep it in v2 for the compatibility

[github-actions]

Package Changes Through 8bc1440

There are 4 changes which include tauri-bundler with minor, tauri-cli with minor, tauri-utils with minor, tauri-build with minor

Planned Package Versions

The following package releases are the planned based on the context of changes in this pull request.

package	current	next
tauri-utils	2.9.1	2.10.0
tauri-bundler	2.9.1	2.10.0
tauri-runtime	2.11.1	2.11.2
tauri-runtime-wry	2.11.1	2.11.2
tauri-codegen	2.6.1	2.6.2
tauri-macros	2.6.1	2.6.2
tauri-plugin	2.6.1	2.6.2
tauri-build	2.6.1	2.7.0
tauri	2.11.1	2.11.2
@tauri-apps/cli	2.11.1	2.11.2
tauri-cli	2.11.1	2.12.0

Add another change file through the GitHub UI by following this link.

---

Read about change files or the docs at github.com/jbolda/covector

[amrbashir]

Can you explain how is this confusing? for me at least I think of:

1. README.md -> ./ or just . as $Resource/README.md
2. README.md -> ./folder as $Resource/folder/README.md since it is a file
3. directory -> ./ or just . as $Resource/directory

The one I actually think of as confusing is this:
4. directory -> ./folder as $Resource/folder, it should be $Resource/folder/directory

Overall I think we should be following the behavior of cp command on unix

[Legend-Master]

2. README.md -> ./folder as $Resource/folder/README.md since it is a file

We can not tell if the target ./folder is a folder (we can if it's written as ./folder/ though), so it gives $RESOURCE/folder today, and that's the confusing part

[Legend-Master]

2. README.md -> ./folder as $Resource/folder/README.md since it is a file
3. directory -> ./ or just . as $Resource/directory

I don't think these were the case? At least not when I wrote https://tauri.app/develop/resources/#tab-panel-715 🤔 (I wrote it based on the actual behavior we had I believe)

[amrbashir]

I really don't know how it behaves atm, but if we plan to break this in a new major, I would just suggest being close as possible to cp command, it makes it more obvious and familiar and less confusing

[Legend-Master]

That makes sense, { "README.md": "./folder/" } must be written as ./folder/ not ./folder to put it at $RESOURCE/folder/README.md though