regex warnings in MsftLinuxPatchCore.py?

**Describe the bug**
I see the following in my journalctl logs:

```
Aug 22 00:36:41 sr-monitor systemd[1]: Starting MsftLinuxPatchAutoAssess.service - Microsoft Azure Linux Patch Extension - Auto Assessment...
Aug 22 00:36:41 sr-monitor bash[143561]: /var/lib/waagent/Microsoft.CPlat.Core.LinuxPatchExtension-1.6.62/MsftLinuxPatchCore.py:7451: SyntaxWarning: invalid escape sequence '\_'
Aug 22 00:36:41 sr-monitor bash[143561]: """ Fetches pid from the error message by searching for the text 'pid' and returns the process tree with all details.
Aug 22 00:36:41 sr-monitor bash[143561]: /var/lib/waagent/Microsoft.CPlat.Core.LinuxPatchExtension-1.6.62/MsftLinuxPatchCore.py:7468: SyntaxWarning: invalid escape sequence '\d'
Aug 22 00:36:41 sr-monitor bash[143561]: regex = re.compile(' pid \d+')
Aug 22 00:36:41 sr-monitor bash[143561]: /var/lib/waagent/Microsoft.CPlat.Core.LinuxPatchExtension-1.6.62/MsftLinuxPatchCore.py:7476: SyntaxWarning: invalid escape sequence '\d'
Aug 22 00:36:41 sr-monitor bash[143561]: regex = re.compile('\d+')
```

Is this a bug?

**To Reproduce**
Steps to reproduce the behavior:
1. Create Azure Ubuntu VM
2. Enable LinuxPatchExtension
3. Watch the logs

**Expected behavior**
No regex warnings

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Desktop (please complete the following information):**
- OS: ubuntu
- Browser N/A
- Version 24_04-lts

**Smartphone (please complete the following information):**
- Device: [e.g. iPhone6]
- OS: [e.g. iOS8.1]
- Browser [e.g. stock browser, safari]
- Version [e.g. 22]

**Additional context**
Add any other context about the problem here.

Start in MsftLinuxPatchCore.py at lines 7451, 7468, and 7476, then reproduce the issue on an Ubuntu 24.04 Azure VM while watching the extension logs. Verify that the affected regex handling no longer emits invalid escape sequence warnings during LinuxPatchExtension startup.

Written by the indexing model from the issue text.