test: remove unnecessary DUNE_CONFIG__LOCK_DEV_TOOL flag from tests

The DUNE_CONFIG__LOCK_DEV_TOOL flag only affects `dune tools exec`
behavior. Remove it from `dune tools install` and `dune tools env`
commands where it has no effect.

Co-Authored-By: Sachin <sachinbeniwal0101@gmail.com>
Signed-off-by: Sachin Beniwal <s474996633@gmail.com>

Author: benodiwal

test/blackbox-tests/test-cases/pkg/ocamlformat/ocamlformat-wrapper.t

@@ -7,7 +7,7 @@ Exercise running the ocamlformat wrapper command.
   $ make_ocamlformat_opam_pkg "0.26.2"
   $ make_project_with_dev_tool_lockdir
 
-  $ DUNE_CONFIG__LOCK_DEV_TOOL=enabled dune tools install ocamlformat
+  $ dune tools install ocamlformat
   Solution for _build/.dev-tools.locks/ocamlformat:
   - ocamlformat.0.26.2
 

test/blackbox-tests/test-cases/pkg/ocamllsp/dev-tool-ocamllsp-basic.t

@@ -38,6 +38,6 @@ Then exec runs it:
 
 Make sure that after evaling the output of 'dune tools env', the first ocamllsp
 executable in PATH is the one installed by dune as a dev tool.
-  $ DUNE_CONFIG__LOCK_DEV_TOOL=enabled eval $(dune tools env)
+  $ eval $(dune tools env)
   $ which ocamllsp
   $TESTCASE_ROOT/_build/_private/default/.dev-tool/ocaml-lsp-server/target/bin/ocamllsp