Remove unused/obsolete source type field from frames metadata (#150013)

## Summary
We don't use the source type for frames, but parse it from the query
response.

In the near future, we remove this field completely from the
`profiling-stackframes` index, because we have no reliable way to
determine the type of source code for a frame of type 'native' or
'kernel'.
For interpreted languages we have this information stored in the
`profiling-stacktraces` index.

x-pack/plugins/profiling/server/routes/search_stacktraces.test.ts

@@ -59,7 +59,6 @@ describe('Stack trace response operations', () => {
           function_name: 'pthread_create',
           function_offset: 0,
           line_number: 0,
-          source_type: 5,
         },
       },
       executables: {
@@ -89,7 +88,6 @@ describe('Stack trace response operations', () => {
             FunctionName: 'pthread_create',
             FunctionOffset: 0,
             LineNumber: 0,
-            SourceType: 5,
           },
         ],
       ]),
@@ -134,7 +132,6 @@ describe('Stack trace response operations', () => {
           function_name: 'pthread_create',
           function_offset: undefined,
           line_number: undefined,
-          source_type: undefined,
         },
       },
       executables: {
@@ -164,7 +161,6 @@ describe('Stack trace response operations', () => {
             FunctionName: 'pthread_create',
             FunctionOffset: null,
             LineNumber: null,
-            SourceType: null,
           },
         ],
       ]),

x-pack/plugins/profiling/server/routes/search_stacktraces.ts

@@ -40,7 +40,6 @@ export function decodeStackTraceResponse(response: StackTraceResponse) {
       FunctionName: value.function_name,
       FunctionOffset: value.function_offset,
       LineNumber: value.line_number,
-      SourceType: value.source_type,
     } as StackFrame);
   }
 

x-pack/plugins/profiling/server/routes/stacktrace.ts

@@ -334,7 +334,6 @@ export async function mgetStackFrames({
         FunctionName: frame._source!.Stackframe.function?.name,
         FunctionOffset: frame._source!.Stackframe.function?.offset,
         LineNumber: frame._source!.Stackframe.line?.number,
-        SourceType: frame._source!.Stackframe.source?.type,
       };
       stackFrames.set(frame._id, stackFrame);
       frameLRU.set(frame._id, stackFrame);