Add delete_examples to Client library

[Joshua-Briggs]

Feature request

Currently there is a function called delete_example, which takes in only one example at a time, but for me I want to get rid of all my examples, I've also added a function that would basically do that and will also show details in-case your interested in adding it to the lib:

Motivation

Let's say your working with a big dataset, and you want to use only parts of that dataset at a time, For me, I don't want to have repeat examples going into the same evaluation function, so this eliminates that.

[hinthornw]

Bulk examples deletion makes sense (we have an API endpoint, just need the SDK sugar), but not for evaluating on a subset of the dataset.

For that you'd just want to pick which examples to evaluate.

https://docs.smith.langchain.com/evaluation/how_to_guides/dataset_subset#evaluate-on-a-filtered-view-of-a-dataset