fix: env macro multiline support

[LNSD]

Context and problem description

The test_with::env and test_with::no_env macros fail to handle properly the following multiline env vars case:

#[test_with::env(
    IT_SOME_LONG_ENV_VAR_NAME_TEST_URL,
    IT_SOME_LONG_ENV_VAR_NAME_TEST_AUTH_TOKEN
)]
#[tokio::test]
async fn some_test() {}

This is problematic since it interferes with rustfmt, i.e., cargo fmt command automatically changes the long attribute lines in a multiline format.

A possible workaround would be to annotate the test with the #[rustfmt::skip] so the macro attributes are not laid out in separate lines:

#[rustfmt::skip]
#[test_with::env(IT_SOME_LONG_ENV_VAR_NAME_TEST_URL,IT_SOME_LONG_ENV_VAR_NAME_TEST_AUTH_TOKEN)]
#[tokio::test]
async fn some_test() {

Proposed solution

To fix the issue, I introduced the sanitize_env_vars_attr(...) function that properly handles the macro attributes arguments, removing any whitespace character and obtaining a slice containing the sanitized environment variable names.

Additionally, I added some unit tests covering the check_env_condition, check_no_env_condition, and sanitize_env_vars_attr functions.

[LNSD]

I am not sure why the Lint/lint check is failing. But it seems unrelated to the code changes introduced in this PR

[yanganto]

Nice catch. I will handle on the linter, thanks for the PR