Environment Variable BITBUCKET_CLONE_DIR is wrongly set when using Runners

Issue Summary

Runner images more recent than bitbucket-pipelines-runner:1.274 are setting the wrong value to the BITBUCKET_CLONE_DIR default environment variable.
The correct value, which is the path where the repository is cloned into, is

/opt/atlassian/pipelines/agent/build

But the variable is currently set with a path in the /temp folder :

/tmp/<runner_id>/build

When trying to access the path in /tmp/<runner_id>/build, it throws an error that this folder does not exist. The files from the repository are still cloned to /opt/atlassian/pipelines/agent/build

Steps to Reproduce

1. Configure a Pipeline to use Runners
2. Use a runners image more recent than bitbucket-pipelines-runner:1.274
3. Try to access the repository set on $BITBUCKET_CLONE_DIR environment variable

Expected Results

The variable $BITBUCKET_CLONE_DIR should be populated with the path /opt/atlassian/pipelines/agent/build, which is the actual folder where the repository is being clone into.

Actual Results

The variable $BITBUCKET_CLONE_DIR has it's values set to /tmp/<runner_id>/build in runners image after 1.274.

Workaround

Use the hard coded path /opt/atlassian/pipelines/agent/build instead of $BITBUCKET_CLONE_DIR variable until the issue is fixed