When TLR feature is disabled, assign ILR during instance level requests creation

Overview:

When creating the instance level request via mod-patron, the user receives the error. This happens because on mod-circulation side we are still looking for the request level field in the json from the mod-patron, which does not pass tit any more.
Steps to Reproduce:

1. Log into some FOLIO environment as User X
2. Attempt to place instance level request with the TLR feature disabled

Expected Results:

An item level request is created.
Actual Results:

{ "code": 500, "errorMessage": "Failed to place a request for the instance. Reasons: \nvalidation failure:\nreason: \"requestLevel must be one of the following: \"Item\"\", parameters: key: requestLevel, value: null%nvalidation failure:\nreason: \"requestLevel must be one of the following: \"Item\"\", parameters: key: requestLevel, value: null%nvalidation failure:\nreason: \"requestLevel must be one of the following: \"Item\"\", parameters: key: requestLevel, value: null%nvalidation failure:\nreason: \"requestLevel must be one of the following: \"Item\"\", parameters: key: requestLevel, value: null%nvalidation failure:\nreason: \"requestLevel must be one of the following: \"Item\"\", parameters: key: requestLevel, value: null%nvalidation failure:\nreason: \"requestLevel must be one of the following: \"Item\"\", parameters: key: requestLevel, value: null%nvalidation failure:\nreason: \"requestLevel must be one of the following: \"Item\"\", parameters: key: requestLevel, value: null%nvalidation failure:\nreason: \"requestLevel must be one of the following: \"Item\"\", parameters: key: requestLevel, value: null%nvalidation failure:\nreason: \"requestLevel must be one of the following: \"Item\"\", parameters: key: requestLevel, value: null"}

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