fusefs: fix some bugs updating atime during close

When using cached attributes, we must update a file's atime during
close, if it has been read since the last attribute refresh. But,

• Don't update atime if we lack write permissions to the file or if the file system is readonly.
• If the daemon fails our atime update request for any reason, don't report this as a failure for VOP_CLOSE.

PR: 270749
Reported by: Jamie Landeg-Jones <jamie@catflap.org>
Sponsored by: Axcient
Reviewed by: pfg
Differential Revision: https://reviews.freebsd.org/D41925

(cherry picked from commit fb619c94c679e939496fe0cf94b8d2cba95e6e63)

fusefs: fix unused variables from fb619c94c67

PR: 270749
Reported by: cy
Sponsored by: Axcient

(cherry picked from commit e5236d25f2c0709acf3547e6af45f4bb4eec4f02)