Merge handleAddPod with handleUpdatePod.

[xujunjie-cover]

ValidatePodCidr and create lsp only in handleAddPod before;
For hotplug and hotunplug nic for a running pod. we also need support when update pod.
so merge handleAddPod with handleUpdatePod to handleAddPodOrUpdatePod.

• Make sure you have followed Kube-OVN Code Style.

What type of this PR

Examples of user facing changes:

• Features

Which issue(s) this PR fixes:

Fixes #2520

[github-actions]

• The commit message should be more descriptive and informative. It should clearly state what changes were made and why.
• There are no potential bugs or format errors in the patch diff.
• It is difficult to assess performance issues without further context on the codebase and the changes made.
• Ways to improve could include adding comments to explain complex logic, using more descriptive variable names, and following consistent coding conventions throughout the codebase.

[github-actions]

• The commit message should be more descriptive and informative. It should clearly state what changes were made and why.
• There are no potential bugs mentioned in the commit message, but it would be helpful to have a brief overview of any potential issues that were addressed or introduced.
• The format of the code patch diff looks fine.
• There is no mention of performance improvements or issues in the commit message. It would be helpful to know if any changes were made to improve performance or if there are any potential performance issues to be aware of.
• It would be helpful to have more details on how the code could be further improved or optimized.

[oilbeater]

Can we use isPodAlive?

[oilbeater]

should check if pod.Annotations is nil here

[oilbeater]

allocte -> allocate

[github-actions]

• The commit message should be more descriptive and informative. It should clearly state what changes were made and why they were necessary.
• There are no potential bugs or format errors in the patch diff.
• It is difficult to assess performance issues without more context about the code being modified.
• Ways to improve could include adding comments to explain complex logic, refactoring repetitive code, or optimizing algorithms for better efficiency. However, it is difficult to provide specific suggestions without more information about the code being modified.