doc: mark Bluetooth on nRF54L15 as supported

Bluetooth on nRF54L15 is officially supported

Signed-off-by: Yuxuan Cai <[email protected]>

Author: yuxCai

doc/nrf/releases_and_maturity/software_maturity.rst

@@ -197,7 +197,7 @@ The following table indicates the software maturity levels of the support for ea
      - Supported
      - Supported
      - Experimental
-     - Experimental
+     - Supported
      - --
      - --
      - --