Fix GN examples workflow not saving the outputs

[mspang]

Fix GN examples workflow not uploading artifacts.

[andy31415]

The binary upload names will be used for bloat check. Could we make the BUILD_TYPE be something like 'gn_nrf' and such so that bloat check compares the right versions?

Alternatively we can remove the uploading of binaries from the autotools build. The binary upload is for bloat purpose only anyway. If we go this latter path, there will be a time where gn builds will be bloat checked against the autotools versions.

[mspang]

Changed to gn_nrf and gn_linux.

[github-actions]

Size increase report for "nrf-example-build"

File	Section	File	VM

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-nrf52840-lock-example.out and ./pull_artifact/chip-nrf52840-lock-example.out:

sections,vmsize,filesize

[github-actions]

Size increase report for "linux-example-build"

File	Section	File	VM

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-standalone-demo.out and ./pull_artifact/chip-standalone-demo.out:

sections,vmsize,filesize

[github-actions]

Size increase report for "esp32-example-build"

File	Section	File	VM

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-wifi-echo.elf and ./pull_artifact/chip-wifi-echo.elf:

sections,vmsize,filesize