docs: Remove extra "and" in external data page (open-policy-agent#3733)

Signed-off-by: jun.gu <jun.gu@easystack.cn>
Signed-off-by: Dolev Farhi <farhi.dolev@gmail.com>

docs/content/external-data.md

@@ -47,7 +47,7 @@ The file-ownership system may be the one that is asking for an authorization dec
 ### Flow
 1. OPA-enabled software gathers relevant metadata (and caches it for subsequent requests)
 1. OPA-enabled software sends `input` to OPA including the external data
-1. Policy makes decisions based on external data included in `input` and
+1. Policy makes decisions based on external data included in `input`
 
 {{< figure src="data-input.png" width="60" caption="Input flow" >}}