task with an env exports the environment variable ?

[saraedum]

Checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pixi, using pixi --version.

Reproducible example

$ cat pixi.toml
[project]
name = "noname"
platforms = ["linux-64"]
channels = ["conda-forge"]

[tasks]
with = { cmd = "/usr/bin/env | grep '?'", env = { ARGUMENT = "hello" } }
without = { cmd = "/usr/bin/env | grep '?'" }
$ pixi run without
✨ Pixi task (without): /usr/bin/env | grep '?'
$ pixi run with
✨ Pixi task (with): /usr/bin/env | grep '?'
?=0

Issue description

Setting an environment variable on the task level also sets the environment variable ?. This breaks tools such as automake.

Expected behavior

Only the environment variables specified in the env should be set.

[saraedum]

This also happens when putting an && into the command:

[project]
name = "noname"
platforms = ["linux-64"]
channels = ["conda-forge"]

[tasks]
with = { cmd = "/bin/true && /usr/bin/env | grep '?'" }
without = { cmd = "/usr/bin/env | grep '?'" }