Remove updateAccountsCreationSettings/listAccountsCreationSettings operations

[felixwa]

Remove these 2 operations because we will leverage global policy to
allow enduser to enable/disable Cognitive Services accounts creation in
future. Not in our RP level anymore.
We have not released SDK or PS etc. so we won't change version this
time.

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[AutorestCI]

No modification for Python

[AutorestCI]

No modification for Ruby

[AutorestCI]

No modification for NodeJS