Character count overflow in source name

Currently, the maximum number of characters for a source (free-text) is 50. However, this is insufficient for providing a proper citation or even the full name of some books. As a result, the following error occurs:

I believe this character limitation is due to display constraints. As discussed in class #436 regarding the multi-source approach, we could increase the length of the source input, provided that sources are not displayed on the instrument detail page.