[chore] Fix make update-otel on macOS

[jade-guiton-dd]

Description:

When working on #35580, it seemed that make update-otel was not properly updating the builder-config.yaml files. I traced this down to the updatehelper script not working as intended. This turned out to be because it uses some features of the sed utility which do not exist on macOS, causing no updates to be made.

The \s (whitespace) regex class is a GNU extension for sed; the POSIX-compatible equivalent is [[:space:]] (related SO question).

Moreover, on macOS, the -i (in-place) option requires an argument, even if empty; otherwise the -e following it is parsed as that argument, creating an unnecessary backup file (related SO question).

Testing:

I manually tested this change as part of developing the aforementioned PR; the script seems to work on macOS now. It would be good for someone to test this change on Linux to make sure nothing has broken there.

[dmitryax]

@jade-guiton-dd, can you please validate it on a linux VM as well? I think everyone runs MacOS locally. Someone has to spin up a linux VM :)

[jade-guiton-dd]

After testing on a Linux device, it looks like the \s change works fine. The -i change also works, but prints a lot of error messages (sed: can't read : No such file or directory, because the '' is interpreted as a second input file). After actually reading the whole SO thread I linked above, it seems like there is no clean portable way of using sed in-place without creating backup file... I'll modify the PR to create a backup file and immediately delete it, which is a somewhat janky solution, but it works.