GH-45775: [C++] Use dict.get() in Meson configuration (#45776)

### Rationale for this change

This change cuts down on the verbosity of the Meson configuration

### What changes are included in this PR?

dict.get() with an empty list default value is used in lieu of requiring every dictionary to create keys with empty list values, where applicable

### Are these changes tested?

Yes

### Are there any user-facing changes?

No
* GitHub Issue: #45775

Authored-by: Will Ayd <william.ayd@icloud.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>

Author: WillAyd

cpp/src/arrow/meson.build

@@ -44,8 +44,6 @@ arrow_components = {
             'array/util.cc',
             'array/validate.cc',
         ],
-        'include_dirs': [],
-        'dependencies': [],
     },
     'arrow_compute': {
         'sources': [
@@ -78,8 +76,6 @@ arrow_components = {
             'compute/kernels/vector_selection_internal.cc',
             'compute/kernels/vector_selection_take_internal.cc',
         ],
-        'include_dirs': [],
-        'dependencies': [],
     },
     'arrow_io': {
         'sources': [
@@ -149,14 +145,9 @@ arrow_components = {
             'util/utf8.cc',
             'util/value_parsing.cc',
         ],
-        'include_dirs': [],
         'dependencies': [threads_dep],
     },
-    'memory_pool': {
-        'sources': ['memory_pool.cc'],
-        'include_dirs': [],
-        'dependencies': [],
-    },
+    'memory_pool': {'sources': ['memory_pool.cc']},
     'vendored': {
         'sources': [
             'vendored/base64.cpp',
@@ -186,8 +177,6 @@ arrow_components = {
             'vendored/uriparser/UriResolve.c',
             'vendored/uriparser/UriShorten.c',
         ],
-        'include_dirs': [],
-        'dependencies': [],
     },
     'arrow_base': {
         'sources': [
@@ -222,8 +211,6 @@ arrow_components = {
             'c/bridge.cc',
             'c/dlpack.cc',
         ],
-        'include_dirs': [],
-        'dependencies': [],
     },
 }
 
@@ -247,8 +234,6 @@ if needs_integration or needs_tests
                 'integration/json_integration.cc',
                 'integration/json_internal.cc',
             ],
-            'include_dirs': [],
-            'dependencies': [],
         },
     }
 endif
@@ -279,11 +264,7 @@ if needs_ipc
     endif
 
     arrow_components += {
-        'arrow_ipc': {
-            'sources': arrow_ipc_srcs,
-            'include_dirs': [],
-            'dependencies': arrow_ipc_deps,
-        },
+        'arrow_ipc': {'sources': arrow_ipc_srcs, 'dependencies': arrow_ipc_deps},
     }
 endif
 
@@ -302,7 +283,6 @@ if needs_json
                 'json/parser.cc',
                 'json/reader.cc',
             ],
-            'include_dirs': [],
             'dependencies': [rapidjson_dep],
         },
     }
@@ -314,8 +294,8 @@ arrow_includes = [include_dir]
 arrow_deps = []
 foreach key, val : arrow_components
     arrow_srcs += val['sources']
-    arrow_includes += val['include_dirs']
-    arrow_deps += val['dependencies']
+    arrow_includes += val.get('include_dirs', [])
+    arrow_deps += val.get('dependencies', [])
 endforeach
 
 arrow_lib = library(