fix(typescript-axios): Serialize boolean to string in form-data file upload (#18083)

[dvacca-onfido]

Whenever providing a boolean field in a form-data file upload, generated library is not doing any conversion causing the following error being raised: TypeError: data should be a string, Buffer or Uint8Array

Expected:

                localVarFormParams.append('validate_image_quality', String(validateImageQuality) as any);

Received:

                localVarFormParams.append('validate_image_quality', validateImageQuality as any);

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Fixes #18083.

@nicokoenig

[wing328]

cc
@TiFu (2017/07) @taxpon (2017/07) @sebastianhaas (2017/07) @kenisteward (2017/07) @Vrolijkx (2017/09) @macjohnny (2018/01) @topce (2018/10) @akehir (2019/07) @petejohansonxo (2019/11) @amakhrov (2020/02) @davidgamero (2022/03) @mkusaka (2022/04)

[macjohnny]

LGTM