1. Remove useless temporary protobuf deb packages
2. Import dash_api to python3 env
### Why I did it
1. There are some temporary Debian packages,protobuf packages, needs to be deleted
2. The dash-api was installed in the system folder that cannot be imported by the virtual python3 environment. But the testcases of DASH in sonic-mgmt are executed in virtual python3 environment.
##### Work item tracking
- Microsoft ADO **(number only)**: 17417902
#### How I did it
1. Add missed `&&` so that all protobuf debian packaged can be downloaded to the /tmp folder
2. Add ` --system-site-packages ` to env-python so that the system library can be accessed by virtual environment
#### How to verify it
Check the dash_api can be imported in env-python3
```
AzDevOps@46a900cf8477:~$ source env-python3/bin/activate
(env-python3) zegan@46a900cf8477:~$ ls
bin env-python3
(env-python3) zegan@46a900cf8477:~$ python3
Python 3.8.10 (default, May 26 2023, 14:05:08)
[GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import dash_api
>>>
```
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