Revert "doc: develop: tools: Exclude webp images from PDF"

This reverts commit a156b619d4.
Now that Sphinx 7.4 is out, it is possible to use webp images
in the PDF documentation (they're converted to png).

Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>

doc/develop/tools/clion.rst

@@ -58,8 +58,6 @@ not happen, go to :menuselection:`Settings --> Build, Execution, Deployment -->
 #. Click :menuselection:`Add environment --> From file` and select
    ``..\.venv\Scripts\activate.bat``.
 
-   .. only:: html
-
    .. figure:: img/clion_toolchain_mingw.webp
       :width: 600px
       :align: center
@@ -74,8 +72,6 @@ not happen, go to :menuselection:`Settings --> Build, Execution, Deployment -->
 
       -DBOARD=nrf52840dk/nrf52840
 
-   .. only:: html
-
    .. figure:: img/clion_cmakeprofile.webp
       :width: 600px
       :align: center
@@ -170,8 +166,6 @@ your setup is different, make sure to adjust the configuration settings accordin
         * - :guilabel:`TCP/IP port`
           - Auto
 
-   .. only:: html
-
     .. figure:: img/clion_gdbserverconfig.webp
        :width: 500px
        :align: center
@@ -179,8 +173,6 @@ your setup is different, make sure to adjust the configuration settings accordin
 
 #. Click :guilabel:`Next` to set the Segger J-Link parameters.
 
-   .. only:: html
-
     .. figure:: img/clion_segger_settings.webp
        :width: 500px
        :align: center
@@ -201,8 +193,6 @@ Start debugging
    Zephyr tasks are listed in the :guilabel:`Threads & Variables` pane. You can switch between them
    and inspect the variables for each task.
 
-   .. only:: html
-
     .. figure:: img/clion_debug_threads.webp
        :width: 800px
        :align: center