fix(dashboard): changing legend_enabled/legend field to pointer type

[vinay-newrelic]

⚠️ DO NOT MERGE

Description

Currently, if user send the value for legend_enabled as false while creating dashboards, that is currently being ignored, and the default value of true is being used. Fixed it by changing the boolean field to a pointer.

Fixes #2736

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

Please delete options that are not relevant.

• My commit message follows conventional commits
• My code is formatted to Go standards
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes. Go here for instructions on running tests locally.

How to test this change?

Please describe how to test your changes. Include any relevant steps in the UI, HCL file(s), commands, etc

• Step 1
• Step 2
• etc

[shashank-reddy-nr]

Please check this and correct this if required.

[shashank-reddy-nr]

Please link these terraform changes to client-go locally and try to run/test all dashboard related integration tests locally and make sure nothing new test cases are breaking

[vinay-newrelic]

i have ran all the test cases and hence no error has been found . So we are good with changes as of now and no changes is needed as per the pic.

[pranav-new-relic]

Thanks for the review @shashank-reddy-nr.

@vinay-newrelic please change the reference of newrelic-client-go in go.mod, go.sum in this PR (temporarily) so all CI checks (compile, tests etc.) are no longer obstructed and run successfully. This is a general practice we follow to make sure all integration tests pass with the required changes in the Go Client. Once the changes in the Go Client are released, we can then point the newrelic-client-go version reference to the released version of the Go Client, after which the PR may be merged.