askrene-bias-channel: bias call add up.

The channel bias feature is not being used yet by any plugin, so this
hopefully doesn't break any working code.
When askrene-bias-channel is called the bias quantity is added on top of
any previous biased already present on that channel instead of
overwriting it.

Changelog-Changed: askrene-bias-channel: bias call add up.

Signed-off-by: Lagrang3 <lagrang3@protonmail.com>

doc/schemas/askrene-bias-channel.json

@@ -33,6 +33,14 @@
           "The bias, positive being good and negative being bad (0 being no bias).  Useful values are +/-1 through +/-10, though -100 through +100 are possible values."
         ]
       },
+      "relative": {
+        "type": "boolean",
+        "added": "v25.05",
+        "default": false,
+        "description": [
+          "The bias will be added to the previous value."
+        ]
+      },
       "description": {
         "type": "string",
         "description": [

doc/schemas/plugin.json

@@ -297,6 +297,11 @@
             "active": true,
             "dynamic": false
           },
+          {
+            "name": "/root/lightning/plugins/cln-lsps-client",
+            "active": true,
+            "dynamic": false
+          },
           {
             "name": "/root/lightning/plugins/bookkeeper",
             "active": true,
@@ -430,6 +435,11 @@
             "active": true,
             "dynamic": false
           },
+          {
+            "name": "/root/lightning/plugins/cln-lsps-client",
+            "active": true,
+            "dynamic": false
+          },
           {
             "name": "/root/lightning/plugins/bookkeeper",
             "active": true,