Remove deprecated instrumentation message

[kiftio]

What changes are you making?

Remove the instrumentation message which has been marked deprecated in checkout-web for quite some time now

Before you merge

Important

• I've added tests to support my implementation
• I have read and agree with the Contribution Guidelines.
• I have read and agree with the Code of Conduct.
• I've updated the README.

Releasing a new version of the kit?

• I have bumped the version number in the podspec file.
• I have added a Changelog entry.

Releasing a new major version?

• I have bumped the version number in the README.

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Tip

See the Contributing documentation for instructions on how to publish a new version of the library.

[kieran-osgood-shopify]

Some lint warnings to clean up but otherwise looks good to me

[markmur]

Let's hold off on shipping this for now until we have a replacement in place for our monitoring