Compile test plugins as MODULE instead of STATIC

[j-rivero]

Revert part of #2753 which change the compilation of plugins to STATIC.

Should fix #2883 in the gazebo11 branch. Needs to be tested on ARM.

[scpeters]

we still need to test with ARM, but just looking at our other supported platforms, I believe this has fixed the tests on Ubuntu amd64, but the macOS tests are still broken. apparently MODULE libraries have a .so suffix on macOS (while shared libraries end with .dylib, see #800 and this stackover answer), so I think we'll need to update the logic in Plugin.hh in order to load .so files as plugins on macOS

[ 53%] Linking CXX shared module libExceptionModelPluginConstructor.so
...
[ 53%] Linking CXX shared module libExceptionModelPluginInit.so

we don't need to block this PR on macOS; if it fixes Ubuntu amd64 and ARM, we can add some comments to #800 about this and follow up later

[j-rivero]

Needs to be tested on ARM.

Let's try

apparently MODULE libraries have a .so suffix on macOS (while shared libraries end with .dylib, see #800 and this stackover answer), so I think we'll need to update the logic in Plugin.hh in order to load .so files as plugins on macOS

Interesting. I agree on following on #800.

[scpeters]

@j-rivero I just merged with gazebo11, so this should be up to date now. Do you think we can try another ARM test build of this branch?

[scpeters]

arm test build:

• https://build.osrfoundation.org/job/_test_gazebo-ci-pr_any-ubuntu_auto-arm64-gpu-nvidia/3/

[scpeters]

arm test build:

• https://build.osrfoundation.org/job/_test_gazebo-ci-pr_any-ubuntu_auto-arm64-gpu-nvidia/3/

I started another job but it didn't finish

https://build.osrfoundation.org/job/_test_gazebo-ci-pr_any-ubuntu_auto-arm64-gpu-nvidia/4/

[scpeters]

it's looking better; the arm build succeeded, though there are more test failures than normal and the console output suggests a runtime problem

395: Unsupported setsockopt level=0 optname=32
395: Error setting socket option (IP_MULTICAST_IF).
395: Unsupported setsockopt level=0 optname=32
395: Error setting socket option (IP_MULTICAST_IF).
395: Did you set the environment variable IGN_IP with a correct IP address? 
395:   [172.17.0.2] seems an invalid local IP address.
395:   Using 127.0.0.1 as hostname.
395: terminate called after throwing an instance of 'std::out_of_range'
395:   what():  vector::_M_range_check: __n (which is 0) >= this->size() (which is 0)
395: qemu: uncaught target signal 6 (Aborted) - core dumped

https://build.osrfoundation.org/job/_test_gazebo-ci-pr_any-ubuntu_auto-arm64-gpu-nvidia/7/

the windows build is failing though

Scanning dependencies of target gtest_main
Error: dependent 'test\gtest.lib' does not exist.

https://build.osrfoundation.org/job/gazebo-ci-pr_any-windows7-amd64/3203/

[scpeters]

thanks for all the iteration and fixing the changelog!