Fialed test fix: rename fixture session_cross_acc_env_1 (#1586)

### Feature or Bugfix
<!-- please choose -->
- Bugfix


### Detail
- fixed wrong fixture name

### Relates
- <URL or Ticket>

### Security
Please answer the questions below briefly where applicable, or write
`N/A`. Based on
[OWASP 10](https://owasp.org/Top10/en/).

- Does this PR introduce or modify any input fields or queries - this
includes
fetching data from storage outside the application (e.g. a database, an
S3 bucket)?
  - Is the input sanitized?
- What precautions are you taking before deserializing the data you
consume?
  - Is injection prevented by parametrizing queries?
  - Have you ensured no `eval` or similar functions are used?
- Does this PR introduce any functionality or component that requires
authorization?
- How have you ensured it respects the existing AuthN/AuthZ mechanisms?
  - Are you logging failed auth attempts?
- Are you using or adding any cryptographic features?
  - Do you use a standard proven implementations?
  - Are the used keys controlled by the customer? Where are they stored?
- Are you introducing any new policies/roles/users?
  - Have you used the least-privilege principle? How?


By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.

Co-authored-by: Sofia Sazonova <sazonova@amazon.co.uk>

tests_new/integration_tests/core/environment/test_environment.py

@@ -119,5 +119,5 @@ def test_add_consumption_role_unauthorized(client2, session_env2, group1):
     ).contains('UnauthorizedOperation', 'ADD_ENVIRONMENT_CONSUMPTION_ROLES', env_uri)
 
 
-def test_create_crossaccount_env(client5, persistent_cross_acc_env_1, group5):
-    assert_that(persistent_cross_acc_env_1.stack.status).is_in('CREATE_COMPLETE', 'UPDATE_COMPLETE')
+def test_create_crossaccount_env(client5, session_cross_acc_env_1, group5):
+    assert_that(session_cross_acc_env_1.stack.status).is_in('CREATE_COMPLETE', 'UPDATE_COMPLETE')