library: allow "?" in tr_ML3_MT_MM_ID_Req again

Fix MSC test TC_lu_by_imei, which uses tr_ML3_MT_MM_ID_Req with the
default "?" (AnyElement) parameter. It was failing with the following
runtime error:

Dynamic test case error: Performing a valueof or send operation on a non-specific template of enumerated type @L3_Templates.CmIdentityType.

Fixes: 328984591372ad5abf51655a51d45d880bfed182 ("L3_Templates: add enum CmIdentityType")
Related: https://www.eclipse.org/forums/index.php/t/1099816/
Change-Id: Ie7fbe52ac3c0c8f233680dcc311febec77d2ed0b
1 file changed