[workspace] Update dependency abseil_cpp_internal to 20260817.0

tools/workspace/abseil_cpp_internal/patches/inline_namespace.patch

@@ -8,12 +8,12 @@ designed for end-user customization, and that's basically all we're doing here.
 
 --- absl/base/options.h
 +++ absl/base/options.h
-@@ -123,8 +123,8 @@
+@@ -150,8 +150,8 @@
  // be changed to a new, unique identifier name.  In particular "head" is not
  // allowed.
 
  #define ABSL_OPTION_USE_INLINE_NAMESPACE 1
--#define ABSL_OPTION_INLINE_NAMESPACE_NAME lts_20260526
+-#define ABSL_OPTION_INLINE_NAMESPACE_NAME lts_20260817
 +#define ABSL_OPTION_INLINE_NAMESPACE_NAME drake_vendor
 
  // ABSL_OPTION_HARDENED

tools/workspace/abseil_cpp_internal/repository.bzl

@@ -7,11 +7,9 @@ def abseil_cpp_internal_repository(
         name = name,
         repository = "abseil/abseil-cpp",
         upgrade_type = "release",
-        commit = "20260526.0",
-        sha256 = "6e1aee535473414164bf83e4ebc40240dec71a4701f8a642d906e95bea1aea0c",  # noqa
+        commit = "20260817.0",
+        sha256 = "f7e05179df39c45434cad433f5783840bb3788ef322976f9138bc6b72b3a107d",  # noqa
         patches = [
-            ":patches/upstream/include_bmi2intrin.patch",
-            ":patches/upstream/internal_c_symbol.patch",
             ":patches/hidden_visibility.patch",
             ":patches/inline_namespace.patch",
         ],
@@ -21,6 +19,9 @@ def abseil_cpp_internal_repository(
             # uses so that we don't get "duplicate kwarg" errors. Then, add it
             # anywhere that linkopts already appears.
             "sed -i -e 's|linkstatic = 1,||; s|linkopts = |linkstatic = 1, linkopts = |' $(find absl -name BUILD.bazel)",  # noqa
+            # Remove `visibility = ...` annotations for gloop. Drake doesn't use
+            # gloop, so the references fail to resolve at analysis-time.
+            "sed -i -e '/@do_not_use_for_gloop_visibility_only/d;' $(find absl -name BUILD.bazel)",  # noqa
         ],
         mirrors = mirrors,
     )