[feat] make firewallID mutable, propagate it from lmt->lm

[tchinmai7]

What this PR does / why we need it:

• Make the FirewallID mutable on the LinodeMachineTemplate
• Propagate the change from LinodeMachineTemplate -> LinodeMachine
• Update the firewalls attached to a linode when the spec changes

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

TODOs:

• squashed commits
• includes documentation
• adds unit tests
• adds or updates e2e tests

[codecov]

Codecov Report

❌ Patch coverage is 74.07407% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 63.42%. Comparing base (6e6db1b) to head (a796d7b).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...nal/controller/linodemachinetemplate_controller.go	36.36%	11 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #813      +/-   ##
==========================================
+ Coverage   63.20%   63.42%   +0.22%     
==========================================
  Files          71       71              
  Lines        7359     7410      +51     
==========================================
+ Hits         4651     4700      +49     
  Misses       2435     2435              
- Partials      273      275       +2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[tchinmai7]

We're replacing an array with an individual ID - is this OK?

[Copilot]

Pull Request Overview

This PR adds support for mutable FirewallID configurations in LinodeMachineTemplate and propagates firewall changes from LinodeMachineTemplate to LinodeMachine resources. It enables dynamic firewall management for Linode instances.

• Removes immutability constraints on FirewallID fields in both LinodeMachine and LinodeMachineTemplate
• Adds reconciliation logic to propagate firewall changes from templates to machines and update Linode instances
• Introduces new client methods for listing and updating instance firewalls with corresponding mock implementations

Reviewed Changes

Copilot reviewed 13 out of 14 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
api/v1alpha2/linodemachine_types.go	Removes immutability validation for FirewallID field and adds documentation
api/v1alpha2/linodemachinetemplate_types.go	Adds FirewallID field to LinodeMachineTemplateStatus
config/crd/bases/*.yaml	Updates CRD definitions to reflect API changes and remove immutability constraints
clients/clients.go	Adds new interface methods for firewall operations
internal/controller/linodemachine_controller.go	Implements firewall reconciliation logic for LinodeMachine
internal/controller/linodemachinetemplate_controller.go	Adds firewall propagation from template to machines
mock/client.go	Adds mock implementations for new firewall client methods
observability/wrappers/linodeclient/linodeclient.gen.go	Adds tracing wrappers for new firewall methods
go.mod	Updates dependencies
docs/src/reference/out.md	Updates documentation with new field descriptions
Test files	Adds comprehensive test coverage for firewall functionality

Comments suppressed due to low confidence (1)

internal/controller/linodemachinetemplate_controller.go:190

• Missing log statement in reconcileFirewallID function. Consider adding a log message similar to the reconcileTags function to track successful firewall ID updates.

	return nil