Eth hotplug check cable and routable before pinging (Bugfix)

[seankingyang]

Description

Some of the machines (most of the IOT devices) can't ping after plugging the eth cable.
Some of the machines (most of the PC devices) can ping after plugging the eth cable.

In Desktop image, the networking renderer is Networkmanager

It will delay to turn down the eth interface and keep the ip (will not send req to DHCP to get the IP) when unpluggin the cable.

• If the tester remove the cable and connect the cable immediatly, the test case can be pass (This is the work around method for the original script)
• If the tester remove the cable, make sure the NetworkMangager trun the eth interface down, and reconnect the cable back. In this situation, some of the device will get the ip slowly and this test case will fail. But it really can get the original ip and available to ping.

In Server/UC image, the networking renderer is systemd-networkd

It will immediatly turn the interface down when unplugging the cable.

• If the tester remove the cable and reconnect the cable immedatly, this test case will still fail. But it really can get the original ip and available to ping.

Change

Need to make sure the networking renderer actually not routable if remove the cable; it actually routable if reconnect the cable before ping.

Flow

1, Check interface cable state (make sure this eth interface is existed)
2. Ask Tester to remove the eth cable
3. check cable is remove
4. check network renderer is Not routable
5. Ask Tester to reconnect the eth cable
6. check cable is connect
7. check network renderer is routable
8. Ping the gateway

Resolved issues

#1197 ethernet/hotplug-{{ interface }} fails without potential latency
#1260 ethernet/hotplug-.* failed due to unable to ping the host

Tests

PC Desktop image with NetworkManager: https://certification.canonical.com/hardware/202411-35941/submission/409179/
IOT UC image with systemd-networkd: https://certification.canonical.com/hardware/202307-31859/submission/409181/

[codecov]

Codecov Report

Attention: Patch coverage is 97.80220% with 2 lines in your changes missing coverage. Please review.

Project coverage is 49.27%. Comparing base (4305ba1) to head (2c74500).
Report is 38 commits behind head on main.

Files with missing lines	Patch %	Lines
providers/base/bin/eth_hotplugging.py	97.80%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1694      +/-   ##
==========================================
+ Coverage   48.99%   49.27%   +0.27%     
==========================================
  Files         372      373       +1     
  Lines       40321    40472     +151     
  Branches     6811     6841      +30     
==========================================
+ Hits        19757    19943     +186     
+ Misses      19842    19803      -39     
- Partials      722      726       +4     

Flag	Coverage Δ
provider-base	25.73% <97.80%> (+0.93%)	⬆️

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[pieqq]

Thanks for undertaking this big change!

I noticed you used your own retry mechanism for different functions in the script. I recommend using the retry decorator available in checkbox-support (see comments inline below).