Check name duplicate

[amritansh22]

In the model app, when the name of the uploaded models are same, it creates confusion later while choosing the model and error while removing the model. This PR fixes these issues.

So, now when we enter repeated name, we see an error as:

[mgautam98]

@amritansh22 it is not working if I refresh the page remember that the models are persistent in the memory therefore, this feat. also needs to be persistent.

Also, it is not working if I don't refresh, it still uploads the model becaue you need to return after catching the error. Here, it displays it and then continues the execution.

[amritansh22]

@mgautam98 Thanks a lot for pointing out the mistakes. I have fixed them.

[birm]

Thanks for getting this together! I'll merge it before we make another conflict ;)

[mgautam98]

@birm are you sure it's working. The namearr is not being populated with all the model names. Though, model name is saved as soon as you refresh or go to other pages the namearr is again initialised to empty array.

[birm]

Hm, I may have missed something when testing... If there's a a fix to this fix, we'll certainly welcome a PR.