ipam: Reduce git actions noise

[oshoval]

What this PR does / why we need it:
When kubevirt-bot creates PRs, it will trigger the IPAM lane twice, because both
push and pull_request events occur (the bot creates a branch on main, hence push event happens).
The IPAM lane also runs after a PR is merged, because it triggers push.
In order to reduce this noise, lets remove the push event.
The pull_request is enough as long as PRs are used
(and not direct pushes which aren't encouraged, nor monitored anyhow).

Special notes for your reviewer:

Release note:

None

[kubevirt-bot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[oshoval]

Opening the PR did trigger it, lets try to push changes

[oshoval]

pushing changes also worked

we also know that it work for the bot, because the bot had both events triggered
and we removed just one (user uses a fork, hence user doesnt trigger push event, but bot creates branch on main)

P.S atm when the PR is merged, it also triggered a "post submit" due to the push event, so it will stop that from
happening as well (it was not intended to happen)

[oshoval]

lets check if close open trigger the jobs
note - git actions doesnt rebase, but still important to have it upon reopen
(we can fix the auto rebase later, it isnt related here)

[oshoval]

it triggered upon reopen - we are good in this aspect

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[oshoval]

/cc @maiqueb @RamLavi

[oshoval]

Thank you

/approve

[kubevirt-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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