Describe breaking changes for ValueLoadContext in 3.0 release notes

[dtaimanov]

see jmix-framework/jmix#4371

Previously adding alias to Condition of ValueLoadContext worked:

'PropertyCondition.equal("username", "admin");' -> 'PropertyCondition.equal("e.username", "admin");'

Currently, after aligning this behaviour with regular entity LoadContext, this alias is added automatically and previous workaround will cause wrong jpql generation.