fix build error in ascend dockerfile

[CyCle1024]

Motivation

In docker/Dockerfile_aarch64_ascend we have two build errors in last updates:

1. incorrect nnal package name
2. not sourcing CANN set_env.sh, nnal build would be failed in installation

Modification

Add env source and fix package name in docker/Dockerfile_aarch64_ascend

Checklist

1. Pre-commit or other linting tools are used to fix the potential lint issues.
2. The modification is covered by complete unit tests. If not, please add more unit tests to ensure the correctness.
3. If the modification has a dependency on downstream projects of a newer version, this PR should be tested with all supported versions of downstream projects.
4. The documentation has been modified accordingly, like docstring or example tutorials.

[CyCle1024]

Builded successfully on Atlas 800T A2 with kunpeng920 cpu, ran simple demo successfully:

1. ascend graph mode on llama2-chat-7b
2. ascend eager mode on InternVL-Chat-V1-5