Fix: esptool_py incorrectly assumed target name equals binary name (IDFGH-11420)

[itavero]

While integrating the ESP-IDF into our existing CMake structure, I've come across quite some hurdles.
Most I've been able to fix in our CMake files, however this one I could not.

Most of the targets created by the esptool_py component assume that the EXECUTABLE IDF build property (which contains the name of the CMake executable target) always equals the name of the created binary.

This is however not always true. For instance, in our setup we use CMAKE_EXECUTABLE_SUFFIX_C and CMAKE_EXECUTABLE_SUFFIX_CXX in our toolchain file (both set to .elf).
If we do add_executable(my_app), the target binary file would actually be my_app.elf.

In order to fix this, I've updated it to use the TARGET_FILE generated expression. That way we also no longer need the EXECUTABLE_DIR IDF build property here.

I've fixed this on v5.0.1 (as that's the ESP-IDF version I'm currently trying to integrate), but I assume it should be easy to apply the same fix to newer versions and the master branch as well.

Note that this problem might exist in multiple places where EXECUTABLE is being used.
While going through the ESP-IDF code base, I even noticed that a few places actually already seem to use the TARGET_FILE expression.
To be honest the property name might be somewhat confusing as well, as it is actually the executable target.

[CLAassistant]

All committers have signed the CLA.

[igrr]

Thanks for the fix @itavero!

We can't merge the PR as is, because we have to first make the fix in the master branch. We will rebase your commit to master and later will backport the change to the existing release branches (release/v5.2, release/v5.1, release/v5.0).

[github-actions]

	Messages
📖	Good Job! All checks are passing!

---

👋 Welcome itavero, thank you for your first contribution to espressif/esp-idf project!

📘 Please check Contributions Guide for the contribution checklist, information regarding code and documentation style, testing and other topics.

🖊️ Please also make sure you have read and signed the Contributor License Agreement for espressif/esp-idf project.

Pull request review and merge process you can expect

Espressif develops the ESP-IDF project in an internal repository (Gitlab). We do welcome contributions in the form of bug reports, feature requests and pull requests via this public GitHub repository.

1. An internal issue has been created for the PR, we assign it to the relevant engineer
2. They review the PR and either approve it or ask you for changes or clarifications
3. Once the Github PR is approved, we synchronize it into our internal git repository
4. In the internal git repository we do the final review, collect approvals from core owners and make sure all the automated tests are passing
   • At this point we may do some adjustments to the proposed change, or extend it by adding tests or documentation.
5. If the change is approved and passes the tests it is merged into the master branch
6. On next sync from the internal git repository merged change will appear in this public Github repository

---

Generated by 🚫 dangerJS against 5293eff

[itavero]

@igrr I've rebased it on master and did a force push. Looking forward to a backport to v5.0.

[fhrbata]

sha=5293eff4cdd8545266bafdec6fe98522bbaf9c28