test: see if xapian will build with 3.13beta1

isue2551338 xapian doesn't build in CI for 3.13 python

Also add an if: clause (looking for 3.14 so 3.13 will build).
If xapian fails to build the if: clause will allow me to skip
download/unpack and configure for this step saving runtime.

.github/workflows/ci-test.yml

@@ -224,6 +224,7 @@ jobs:
               pip install Markdown; fi
 
       - name: Install xapian
+        if: matrix.python-version != '3.14'
         run: |
           set -xv
           sudo apt-get install libxapian-dev
@@ -254,7 +255,7 @@ jobs:
             diff -u configure.FCS configure || true; \
             ./configure --prefix=$VIRTUAL_ENV --with-python3 --disable-documentation; \
           fi
-          case "$PYTHON_VERSION" in "3.13") echo skipping xapian build;; *) make && sudo make install; esac
+          case "$PYTHON_VERSION" in "3.14") echo skipping xapian build;; *) make && sudo make install; esac
 
       - name: Test build roundup and install locale so lang tests work.
         run: |