[bug#51931] [PATCH core-updates-frozen] gnu: sbcl-cl-webkit: Update to 3.4.0.

[Kaelyn]

This patch could probably also apply to the main branch, but I discovered that 
sbcl-cl-webkit would not build when updating a system that was already on 
core-updates-frozen but hadn't been updated in a while.

The most relevant snippet of the failed build's log is:

; wrote 
/gnu/store/ql3zbp096vc0pmlaxk99p8s3xwyhmf0r-sbcl-cl-webkit-3.0.0/lib/common-lisp/sbcl/cl-webkit/webkit2/webkit2.init-tmp9V47YWQF.fasl
; compilation finished in 0:00:00.012
Unhandled LOAD-FOREIGN-LIBRARY-ERROR in thread #<SB-THREAD:THREAD "main thread" 
RUNNING
                                                  {100B8202F3}>:
  Unable to load any of the alternatives:
   
("/gnu/store/ixi7vwjvwc7ci6v28y1n9i2hmh9scf0f-webkitgtk-2.34.1/lib/libwebkit2gtk-4.0.so"
    
"/gnu/store/ixi7vwjvwc7ci6v28y1n9i2hmh9scf0f-webkitgtk-2.34.1/lib/libwebkit2gtk-4.0.so.37")

Backtrace for: #<SB-THREAD:THREAD "main thread" RUNNING {100B8202F3}>
0: (SB-DEBUG::DEBUGGER-DISABLED-HOOK #<LOAD-FOREIGN-LIBRARY-ERROR "Unable to 
load any of the alternatives:~%   ~S" {10092CE233}> #<unused argument> :QUIT T)
1: (SB-DEBUG::RUN-HOOK SB-EXT:*INVOKE-DEBUGGER-HOOK* 
#<LOAD-FOREIGN-LIBRARY-ERROR "Unable to load any of the alternatives:~%   ~S" 
{10092CE233}>)
2: (INVOKE-DEBUGGER #<LOAD-FOREIGN-LIBRARY-ERROR "Unable to load any of the 
alternatives:~%   ~S" {10092CE233}>)

According to the change log at https://github.com/joachifm/cl-webkit, support 
for libwebkit2gtk-4.1.so as found in 
ixi7vwjvwc7ci6v28y1n9i2hmh9scf0f-webkitgtk-2.34.1 was added in version 3.3.0.