[BUG] judged wrong app type when buildcontext is both have yaml and shell files

[kakaZhou719]

What happen?

If the app type cannot be judged, user needs to write APPCMDS in the kubefile.

for example:

i have a app contains yaml file and shell:

ls buildcontext: 
nginx.yaml
ns.yaml
start.sh

i just want to copy all yaml and shell files , then use start.sh to launch my app.

kubefile:

FROM scratch
APP myapp local://buildcontext
LAUNCH myapp

this will judge myapp its a yaml type.

Relevant log output?

No response

What you expected to happen?

No response

How to reproduce it (as minimally and precisely as possible)?

No response

Anything else we need to know?

No response

What is the version of Sealer you using?

No response

What is your OS environment?

No response

What is the Kernel version?

No response

Other environment you want to tell us?

• Cloud provider or hardware configuration:
• Install tools:
• Others:

[kakaZhou719]

Duplicated issue with #1993