Use RNTupleReader::RActiveEntryToken

[Dr15Jones]

PR description:

This is meant to avoid having a cluster go away before all data from it has been read.

PR validation:

Code compiles in a new enough version of ROOT.

[cmsbuild]

cms-bot internal usage

[cmsbuild]

-code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-50617/48815

ERROR: Build errors found during clang-tidy run.

src/FWIO/RNTupleTempInput/src/RootRNTuple.cc:90:47: error: no member named 'CreateActiveEntryToken' in 'ROOT::RNTupleReader' [clang-diagnostic-error]
   90 |         activeEntryTokens_.push_back(reader_->CreateActiveEntryToken());
      |                                      ~~~~~~~~~^
src/FWIO/RNTupleTempInput/src/RootRNTuple.h:209:38: error: no member named 'RActiveEntryToken' in 'ROOT::RNTupleReader' [clang-diagnostic-error]
  209 |     std::vector<ROOT::RNTupleReader::RActiveEntryToken> activeEntryTokens_;
      |                                      ^~~~~~~~~~~~~~~~~
Suppressed 1077 warnings (1075 in non-user code, 2 NOLINT).
--
gmake: *** [config/SCRAM/GMake/Makefile.coderules:129: code-checks] Error 2
gmake: *** [There are compilation/build errors. Please see the detail log above.] Error 2

[Dr15Jones]

hold