chore(java-accessapproval): remove extra generated samples (#12560)

Remove extra generated samples under
`java-accessapproval/google-cloud-accessapproval/samples/snippets/generated`.
The generated samples maintained by the generator are located in
`google-cloud-java/java-accessapproval/samplessnippets/generated`.

These deleted samples were introduced in
[commit](69e4e93).
From the commit message it seems to meant for short term testing and is
accidentally left in the code base:
`chore: include java generated samples
testing recent changes in gapic-generator-java 2.7.0 to write generated
samples to files`

Author: zhumin8