Removes non string helper functions out of stringhelpers.go (IsBeingDeleted)

[melonrush13]

Closes #414

What this PR does / why we need it:
Stringhelpers.go contains string helper functions. IsBeingDeleted is not a string helper function and is no longer being used. This PR removes the function from the code base.

Special notes for your reviewer:

How does this PR make you feel:

If applicable:

• this PR contains documentation
• this PR contains tests

[melonrush13]

@cnadolny I think you are in the process of removing Azure Data Lake operator right now if I'm correct? I wanted to tag you in this just so you are aware I deleted some functions which might touch files you are looking at!

[WilliamMortlMicrosoft]

lgtm

[WilliamMortlMicrosoft]

the conflicts are that those files are gone

[WilliamMortlMicrosoft]

I'm re-running the pipeline, but observed this:

--- FAIL: TestMySQLHappyPath (1057.03s)
    helpers.go:278: 
        	Error Trace:	helpers.go:278
        	            				helpers.go:211
        	            				mysql_combined_test.go:36
        	Error:      	Expected nil, but got: &errors.errorString{s:"Expected: \n\t\t\t\t\tStatus.Message to contain successfully provisioned\n\t\t\t\t\tStatus.Provisioned to be true\n\t\t\t\tActual:\n\t\t\t\t\tMessage: 'mysql.ServersCreateFuture: asynchronous operation has not completed'\n\t\t\t\t\tProvisioned: false\n\t\t\t\t"}
        	Test:       	TestMySQLHappyPath
        	Messages:   	wait for *v1alpha1.MySQLServer to provision

[melonrush13]

I'm re-running the pipeline, but observed this:

--- FAIL: TestMySQLHappyPath (1057.03s)
    helpers.go:278: 
        	Error Trace:	helpers.go:278
        	            				helpers.go:211
        	            				mysql_combined_test.go:36
        	Error:      	Expected nil, but got: &errors.errorString{s:"Expected: \n\t\t\t\t\tStatus.Message to contain successfully provisioned\n\t\t\t\t\tStatus.Provisioned to be true\n\t\t\t\tActual:\n\t\t\t\t\tMessage: 'mysql.ServersCreateFuture: asynchronous operation has not completed'\n\t\t\t\t\tProvisioned: false\n\t\t\t\t"}
        	Test:       	TestMySQLHappyPath
        	Messages:   	wait for *v1alpha1.MySQLServer to provision

I got this same err on my cosmos API change too.. :/ I'll paste it to Erin

[WilliamMortlMicrosoft]

HYFR